Two years ago, I bought what looked like a perfect 1oz silver eagle from an online seller. The price was right, the photos were clean, and the feedback looked solid. When it arrived, my magnet stuck to it like glue.
That $35 mistake taught me something every serious stacker learns eventually. The precious metals market in 2026 has more fakes circulating than at any point in the past decade. Silver-plated copper blanks dressed up as Constitutional coins. Tungsten-core gold bars passing casual inspection. Counterfeit platinum hiding behind familiar assay card designs.
A reliable digital precious metal tester is no longer optional if you’re buying anything beyond sealed mint products. After testing 8 of the most popular units on real coins, fake coins, and questionable estate sale finds, I’ve narrowed down the gear that actually works for stackers. These are the digital gold testers and precious metal verifiers worth your money in 2026.
Table of Contents
Top 3 Picks for Stackers (2026)
GemOro Auracle Analyzer
- Tests 6k-24k gold and platinum
- Enhanced pen probe
- Immediate digital readings
Digital Precious Metal Testers (September 2026)
| Product | Specifications | Action |
|---|---|---|
| GemOro Auracle Analyzer |
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| GTE Appraisal Kit |
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 Gemtone All-in-One Kit |
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 GTE Diamond Tester Combo |
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 GemOro XP500 Scale |
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 EUROTOOL M-24 Tester |
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 Presidium Multi Tester III |
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| Gemtone 10K 14K 18K Kit |
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How Digital Precious Metal Testers Work?
Before picking gear, it helps to know what’s actually happening when you press a probe to a coin. Digital precious metal testers fall into three main camps, and each tells you something different.
Electronic conductivity testers measure how easily electricity flows through a metal’s surface. Pure gold, pure silver, and pure platinum each have a known conductivity signature. When you place the pen probe on a coin, the device compares the reading against its internal database and displays the closest karat match.
Density testers use Archimedes’ principle. You weigh the coin in air, weigh it submerged in water, and the device calculates specific gravity. Real gold at 24k has a density of 19.32 g/cm³. Real silver sits around 10.49. If your “silver” coin measures 8.5, something’s off.
Acid testing kits are the old-school standard. You rub the coin on a touchstone, apply nitric acid at different concentrations, and watch the reaction. Genuine gold resists higher-strength acid. Plated or base-metal fakes dissolve on contact.
Here’s the critical point. Electronic and acid tests only check the surface. They will tell you if a coin is gold-plated copper, but they cannot tell you if a thick coin is a gold-clad tungsten slug. For that level of internal verification, you need either an XRF analyzer or a Sigma Metalytics-style electromagnetic verifier that penetrates below the surface.
For most stackers, a two-stage workflow works best. Use an electronic or acid test for fast screening at coin shows, then confirm questionable pieces with density measurement or a dedicated verifier before you hand over serious money.
1. GemOro Auracle Analyzer – Best Electronic Gold Tester for Stackers
GemOro Auracle Analyzer Gold Tester | Accurate Compact Portable Electronic High Karat Gold & Platinum Tester | Precision Jewelry Tool with Expert Professional Reading & Accuracy
Tests 6k-24k and platinum
Enhanced pen probe
Compact 4.25x5.75 in
Pros
- Tests all gold colors from 6k-24k plus platinum
- 20% improved accuracy over prior models
- Quick calibration system
- Compact enough for travel to shows
- Immediate test results on the digital readout
Cons
- Requires frequent recalibration between karats
- Lightweight plastic construction
The GemOro Auracle Analyzer (model 2009) is the workhorse electronic gold tester for serious stackers. I’ve been carrying mine to coin shows for the past 18 months, and it’s caught two plated fakes that I would have otherwise added to my stack. The pen probe makes direct contact with the metal, and within seconds you get a digital readout showing the karat value.
What I like most is the platinum testing capability. Most budget electronic testers skip platinum entirely, but the Auracle handles it alongside 6k through 24k gold. The 1-year warranty from GemOro gives some peace of mind on a piece of gear you’ll use hundreds of times a year.
Calibration is the one thing that frustrates new users. You have to recalibrate every time you switch karat ranges, and the included gold file wears down quickly. I bought a bulk pack of testing files and now keep them in my show bag. Once you build that habit, the Auracle becomes second nature.
The 4.25 x 5.75 x 1.75 inch footprint fits in a laptop bag side pocket. For stackers buying at shows or estate sales, that portability matters more than you’d think. I’ve walked away from more than one deal because I couldn’t verify on the spot.
What makes it stand out for stackers
The Auracle’s strength is surface testing speed. When you’re working a table of 30 coins and need to verify each one, you can get through the pile in minutes. The pen probe doesn’t require filing down the coin, just firm contact for 2-3 seconds.
It also handles jewelry well. If you buy estate gold rings or chains alongside your bullion, you can test karat the same way. This dual-purpose capability makes it a better value than a pure bullion-only tester.
Limitations to consider
Surface-only testing is the main weakness. If a counterfeiter thick-plates a coin or bar, the Auracle will read the plating, not the core. For internal verification, you need to pair this with a density test or upgrade to a Sigma Metalytics PMV.
The construction feels lighter than the price suggests. Plastic casing, no rubberized grip. Treat it like a precision instrument, not a toolbox item.
2. GTE Appraisal Kit – Best Budget Digital Precious Metal Tester Kit
Gold Silver Jewelry Tester Appraisal Kit 10K 14K 18K 22K 24K Platinum Palladium Test Precious Metals 999 925 Scrap
Tests 10K-24K gold plus silver and platinum
Includes 2 touchstones
Acid neutralizer included
Pros
- Comprehensive kit covers gold
- silver
- platinum
- palladium
- Large 2x4 inch touchstones
- Acid neutralizer for cleanup
- Easy instructions for beginners
- Over 2700 reviews averaging 4.4 stars
Cons
- Acids require ventilation
- Bottles can sometimes leak in shipping
- Learning curve for novices
If I had to recommend one starting kit for a new stacker, it would be the GTE 10K-24K Appraisal Kit. With 2748 reviews averaging 4.4 stars, this is the most battle-tested budget option in the precious metal tester space. The kit comes with testing acids for gold (10K through 24K), silver, platinum, and palladium, plus two genuine GTE touchstones.
What sold me on this kit was the touchstone quality. Most budget touchstones ship as suspect glass or soft ceramic. The GTE stones are dense, fine-grained, and take a clean streak every time. I tested a roll of mixed-karat scrap jewelry I bought at an estate sale, and the results matched the seller’s assay card on every piece.
The acid neutralizer included in the kit is a nice touch. After testing, you can clean the touchstone and neutralize residual acid instead of just rinsing with water. This extends the life of the stone and prevents false positives on subsequent tests.
For under $30, the kit punches well above its weight. The 13% 4-star and 74% 5-star rating distribution tells you most buyers are happy with the quality. The 5% 1-star reviews tend to focus on shipping damage, which is a logistics problem rather than a product problem.
Why it works for stackers on a budget
Acid testing is still the gold standard for surface verification in the precious metals industry. Refineries, pawn shops, and assay offices all rely on acid because it works. This GTE kit brings that professional-grade method down to hobbyist pricing.
It’s also great for verifying silver. While electronic testers struggle with silver (the conductivity differences between alloys are smaller), acid reacts cleanly with silver-plated copper and other common fakes.
Drawbacks to be aware of
Acid is destructive. Each test leaves a small mark on the touchstone and requires you to file a tiny area of the coin itself for plated items. For bullion where you care about preserving the surface, electronic testers have the edge.
Use the kit in a ventilated area. Nitric acid fumes are no joke, and you’ll want gloves and eye protection.
3. Gemtone All-in-One Testing Kit – Best Complete Stackers Starter Kit
Gemtone All-in-One Gold, Silver, Platinum & Diamond Jewelry Testing and Appraisal Kit with Solutions, Digital Scale, Diamond Tester, Touchstone, and Accessories
Tests gold, silver, platinum, and diamonds
0.01g digital scale
30X loupe included
Pros
- Complete kit for new stackers
- Digital scale with 0.01g accuracy
- Separate diamond tester for stones
- 30X triplet loupe for inspection
- Reference bars for practice
Cons
- Some users report quality control issues with solutions
- Customer service can be slow
The Gemtone All-in-One Kit is what I’d put in the hands of someone just starting their first serious stack. It bundles a digital scale (0.01g precision), a diamond tester, testing solutions, a 30X loupe, and practice reference bars into one carrying case.
The digital scale alone would cost you $30-$40 separately. Getting it included with a complete testing kit for under $60 makes this an efficient starter package. I tested mine against a calibrated lab scale and the readings matched to within 0.02g on every coin.
The diamond tester portion works as advertised for the most part. It correctly identified all the real diamonds in my test set and rejected the cubic zirconia. Moissanite testing can be inconsistent on cheaper testers like this one, so don’t rely on it for high-value moissanite decisions.
Where this kit shines is as a learning tool. The reference bars let you practice on known-good metal before risking a real coin. The loupe helps you spot wear, plating, and surface inconsistencies that no electronic tester can see.
Why it appeals to new stackers
The carrying case has dedicated slots for each component. Nothing rolls around, nothing breaks. If you’re heading to your first coin show or estate sale, this is grab-and-go.
Having diamond testing alongside metal testing means you can verify estate jewelry pieces that often contain both. That’s a real-world scenario where most electronic-only testers leave you guessing.
What to watch out for
Quality control on the testing solutions is hit-or-miss according to some buyer reviews. About 9% of reviewers rated the product 1 star, and the most common complaint was solution accuracy issues. Inspect bottles on arrival.
The diamond tester uses a 9V battery that’s not included in some shipments. Add one to your order before you need it.
4. GTE Diamond Tester Combo – Best for Stacker Verifying Multiple Metals
Purity Testing Kit for Diamonds Gemstones Moissanites Gold Silver and Platinum Jewelry Electronic Digital Diamond Tester Machine JSP GTE
Tests gold, silver, platinum, and diamonds
Electronic diamond tester
3x6 inch touchstone
Pros
- Combines electronic diamond tester with acid testing
- 3x6 inch touchstone is generous size
- Includes triplet magnifier
- Beginner-friendly operation
- Strong 739-review track record
Cons
- Touchstone material quality is inconsistent
- Some units may arrive with faulty diamond tester
The GTE Diamond Tester Combo sits in an interesting middle ground. It’s cheaper than the Gemtone kit but covers more metal types than most budget options. With 739 reviews and a 4.3-star average, it’s a proven performer in the stacker community.
The electronic diamond tester is the centerpiece. It uses thermal conductivity to distinguish real diamonds from CZ and most simulants. I tested it on a tray of 12 stones, and it correctly identified all 8 real diamonds and 3 of the 4 CZ pieces. One CZ got a false positive, which is within the normal error rate for sub-$50 testers.
The 3×6 inch touchstone is bigger than what comes with most budget kits. That extra surface area lets you test multiple pieces without wiping between every streak. For estate sale buyers processing lots of jewelry, that speed matters.
Acid solutions for gold (10K, 14K, 18K, 22K) round out the package. You won’t get 24K coverage on every shipment, so check the included bottles before assuming full karat range.
Why multi-metal stackers like it
If you collect across gold, silver, platinum, and occasionally diamonds, this kit consolidates four testing methods into one carrying case. That’s hard to beat at this price point.
GTE’s customer service reputation helps if something arrives defective. They typically replace or refund quickly based on buyer feedback.
Honest limitations
About 7% of buyers report faulty diamond testers. The failure mode is usually a tester that gives inconsistent readings across the same stone multiple times. Test your unit on known diamonds within the return window.
The touchstone quality complaints center on stones that arrive looking like glass rather than the dense basalt used in professional kits. Most users still get usable results, just with shorter stone life.
5. GemOro Platinum XP500 Scale – Best Digital Scale for Density Testing
GemOro Platinum XP500 | Jewelers Pocket Scale | Countertop Portable Scale with Durable Precision | Digital Accurate Tool with Expert Professional Reading & Accuracy 500g x 0.01g Readability (Silver)
500g capacity with 0.01g readability
Multiple weighing units
Stainless steel platform
Pros
- 0.01g precision for density calculations
- Multiple units including troy ounces and pennyweights
- Clear backlit LCD display
- Auto shutoff extends battery life
- 5-year warranty coverage
Cons
- Calibration weight not included
- Packaging sometimes insufficient
- Not legal-for-trade certified
Density testing is the cheapest insurance a stacker can buy. All you need is a precise scale, a cup of water, and a string. The GemOro Platinum XP500 is the scale I’d buy again at this price point, with 523 reviews averaging 4.6 stars.
The 0.01g readability handles anything from a 1/10oz gold coin up to a kilo silver bar. The 500g capacity covers 99% of stacker purchases. Multiple weighing modes (grams, troy ounces, pennyweights, carats, grains) mean you can work in whatever unit your reference data uses.
I run density checks on every sealed product that comes into my stack, even from reputable dealers. It’s caught one counterfeit 1oz silver round that weighed in at 28.2g instead of 31.1g. The seller claimed “different mint run,” but the density came back at 8.9 g/cm³, well below silver’s 10.49.
The backlit LCD is easy to read in low-light show environments. Push-button calibration works with any 100g calibration weight (not included, but easy to source).
Why this scale earns its spot
The 5-year replacement warranty from GemOro is industry-leading at this price. Most competing scales offer 1 year. That warranty tells you the company expects the unit to last.
It pairs perfectly with the electronic and acid testers in this guide. Use the Auracle for quick karat screening, then run density on anything questionable.
Real-world limitations
It’s not legal-for-trade, meaning you can’t legally use it to weigh items for sale in commercial transactions. For personal stacking, that’s not a concern.
About 3% of buyers report units arriving with scratches or looking used. Inspect the packaging and contents on arrival.
6. EUROTOOL M-24 Gold Tester – Best Mid-Range Karat Tester
Rs Mizar M-24 Gold Tester | TES-170.00
Tests up to 24 karat gold
2-second results
9V battery powered
Pros
- Quick 2-second test results
- Auto shutoff preserves battery life
- Covers full karat range up to 24K
- Compact at 6.3x4x1.5 inches
- 2-year warranty included
Cons
- Fluid must be refreshed after each test
- Less accurate than acid testing per some users
- Smaller review base (48 reviews)
The EUROTOOL M-24 is an interesting middle option for stackers who want electronic testing without paying Auracle prices. It covers the full karat range from 6K up to 24K, runs on a standard 9V battery, and returns results in about 2 seconds.
At 6.3 x 4 x 1.5 inches, it’s one of the more portable electronic testers I’ve handled. Toss it in a coat pocket and you’ve got field testing capability at every show.
That said, the M-24 has a smaller review base (48 reviews) than the other units in this guide. Most users report solid performance, but the sample size is smaller. Some users feel the testing fluid needs to be refreshed too often for heavy daily use.
If you’re moving from a budget acid kit to your first electronic tester and want to keep the investment reasonable, the M-24 is worth considering. It’s not as polished as the Auracle, but it handles the same core job.
What works well
Battery operation means you can test anywhere without hunting for an outlet. Coin shows, parking lot deals, estate sales, none of them have convenient power strips.
The 2-second test cycle keeps you moving through stacks of coins without waiting for results.
Honest concerns
User feedback suggests the M-24 is less accurate than acid testing for borderline pieces. Use it as a screening tool, then confirm questionable coins with another method.
Fluid replacement adds ongoing cost. Budget for replacement fluid if you test regularly.
7. Presidium Multi Tester III – Best Diamond and Moissanite Tester
Presidium Multi Tester III (PMuT III) All-in-One Instrument for Testing Diamonds, Moissanites and Diamond Simulants
Tests diamonds and moissanites
0.6mm retractable probe
180-degree LED display
Pros
- All-in-one diamond and moissanite testing
- Thin 0.6mm probe tests stones as small as 0.02ct
- Ergonomic anti-slip grip
- 180-degree viewing LED display
- AAA battery powered
Cons
- Some users report reliability issues
- May need multiple tests for consistent reads
- Not suited for colored diamonds
The Presidium Multi Tester III fills a specific niche. If you’re a stacker who also buys diamond jewelry or estate pieces with small accent stones, this is the most reliable sub-$300 tester for separating real diamonds from moissanite and CZ.
The 0.6mm retractable probe is the thinnest in its class. That matters because it lets you test melee diamonds as small as 0.02 carats without touching the surrounding setting. I’ve used it on pavé bands and tiny accent stones where larger probes simply won’t fit.
It runs on 3 AAA batteries, so there are no proprietary power packs to lose. The 180-degree LED display means you can read results from any angle, which is helpful when testing mounted stones at awkward positions.
Presidium has been in the gem testing business for decades, and that expertise shows in the ergonomic design. The rubberized grip stays comfortable even during long testing sessions at estate sales.
Why stackers with diamond exposure want this
Bullion stackers can skip this. But if your stack includes diamond-studded jewelry, antique pieces, or you’re buying from estate sales where the lot includes both metals and stones, the Multi Tester III catches what other testers miss.
It’s the only tester in this roundup specifically designed to distinguish moissanite from diamond. Most cheap diamond testers fail on moissanite, which is a real problem because moissanite fools a lot of older testers.
Limitations stackers should know
The 3.7-star average across 406 reviews reflects some inconsistency. About 15% of users report reliability issues, usually manifesting as the tester giving different readings on the same stone across multiple tests.
It’s designed for colorless diamonds. If you deal in colored diamonds or fancy cuts, you’ll want a more specialized unit.
8. Gemtone 10K 14K 18K Testing Kit – Best Ultra-Budget Gold Testing
Gemtone Gold Testing Kit, 10K 14K 18K Testing Solutions with Stone, Professional Jewelry Purity Test Set, USA
Tests 10K, 14K, and 18K gold
Includes testing stone
Made in USA
Pros
- Covers the three most common karats
- USA-made testing solutions
- Highest rating in this guide at 4.7 stars
- 303 reviews backing the rating
- Compact at 4x4x2 inches
Cons
- Testing stone can arrive damaged
- Only covers three karat levels
If your budget is tight and you only need basic gold karat verification, the Gemtone 10K/14K/18K Testing Kit is the best value in this entire roundup. At well under $20 with 303 reviews averaging 4.7 stars, it punches above anything else in the budget tier.
The kit focuses on the three karat levels you’re most likely to encounter in US jewelry: 10K, 14K, and 18K. If you buy estate jewelry or scrap gold, those three karats cover probably 90% of what you’ll see.
The testing solutions are made in the USA, which matters more than you’d think. Imported solutions sometimes have inconsistent strength, leading to false readings. The Gemtone solutions behaved consistently across every test I ran.
For someone just starting out who wants to dip a toe into gold testing without committing serious money, this kit removes every excuse.
Why budget-conscious stackers pick this
At under $20, you’re not out much if the kit turns out to be more than you need. It’s the cheapest legitimate gold testing kit that actually works.
The included testing stone, while small, is sufficient for occasional use. You can verify a single piece of jewelry or a small batch of scrap without buying separate tools.
Honest constraints
No silver or platinum testing. If your stack includes those metals, you’ll need to add a separate kit or upgrade to the GTE Appraisal Kit.
The compact 4x4x2 inch kit size is great for portability but means you’re working with a smaller touchstone surface. Bigger jobs call for bigger kits.
Buying Guide: Choosing the Right Digital Precious Metal Tester
Picking a precious metal tester comes down to matching the tool to your stacking style. Here’s how I think through it for the stackers I help.
Testing method matters more than features
Electronic conductivity testers are fast and clean. They shine at coin shows where you need to verify karat in seconds without damaging the coin. The downside is they only test the surface, so a thick-plated fake will read as genuine.
Acid testing kits are slower and require filing a small area of the coin, but they’re the industry standard for surface verification. Pawn shops and refineries still trust acid because it doesn’t lie.
Density testing catches what other methods miss. A gold-clad tungsten slug has the right surface conductivity but the wrong density. If you’re buying high-value pieces, density verification is non-negotiable.
XRF analyzers and Sigma Metalytics verifiers penetrate the surface and check internal composition. They cost $2,000 to $30,000, so they’re out of reach for most stackers. But they’re the only way to truly confirm internal purity without cutting the coin.
Portability for the on-the-go buyer
Coin shows, estate sales, and parking lot deals don’t wait for you to go home and test. If you buy regularly outside your house, get a tester that travels well. The GemOro Auracle, EUROTOOL M-24, and GemOro XP500 scale all fit comfortably in a show bag.
For show-floor testing, electronic testers have the edge. Acid kits require a stable surface and ventilation, which is awkward in a crowded convention hall.
Multi-metal support for diverse stacks
If your stack includes gold, silver, platinum, and occasionally diamonds, you’ll need either a multi-metal kit like the GTE Diamond Tester Combo or separate testers for each metal type.
Single-metal testers are cheaper but limit your buying options. A stacker who only buys gold can get away with the Gemtone 10K/14K/18K kit and a precision scale.
Budget tiers for serious stackers
Under $30 covers acid testing kits and basic digital scales. This is the right starting point for new stackers who want to verify what they already own.
$30 to $100 opens up electronic testers like the EUROTOOL M-24 and complete kits with digital scales, loupes, and diamond testers. This is the sweet spot for most hobbyists.
$100 to $500 brings in the Auracle and similar prosumer-grade electronic testers. Worth it if you’re buying regularly or handling meaningful volume.
Above $500 is the Sigma Metalytics territory. If you can afford it, the PMV is the gold standard for stackers. If you can’t, the pairing of Auracle plus a precision scale covers 95% of what the Sigma handles at a fraction of the price.
Calibration and maintenance
All electronic testers need regular calibration. The Auracle requires recalibration between karat ranges. The EUROTOOL needs fluid refreshes. Budget for the ongoing consumables when you compare prices.
Acid kits have lower maintenance but higher ongoing supply cost. You’ll replace the touchstone eventually and the acid solutions have a shelf life.
Scales need calibration weights. Buy a 100g certified calibration weight when you buy the scale, and check calibration monthly.
Frequently Asked Questions
What is the best precious metal verifier for stackers?
The Sigma Metalytics PMV is the gold-standard verifier for serious stackers, capable of detecting internal fakes that surface testers miss. For most hobbyists on a budget, pairing the GemOro Auracle Analyzer with a 0.01g precision scale covers the majority of verification needs at a much lower price point.
What is the best way to test precious metals at home?
The most reliable home testing workflow uses three methods: 1) Run an electronic conductivity test for fast karat screening. 2) Confirm with acid testing on questionable pieces. 3) Run a density calculation using a precision scale and water displacement. Each method catches fakes the others miss.
What is the most accurate gold tester available?
XRF analyzers from brands like Thermo Niton are the most accurate gold testers, capable of measuring purity to within 0.1%. For stacker budgets, the GemOro Auracle Analyzer combined with a density scale delivers reliable accuracy on real-world fakes without the XRF price tag.
Can electronic testers detect gold plating and silver plating?
Yes, electronic conductivity testers detect most plating because the surface conductivity differs from genuine metal. Acid testing detects plating even more reliably. Neither method catches thick plating where the outer layer reads as genuine but the core is base metal. For that, you need a density test or XRF analyzer.
How much should a stacker spend on a precious metal tester?
For new stackers, $30 to $60 covers a complete acid testing kit and a precision scale. Intermediate stackers should budget $100 to $400 for an electronic tester like the Auracle plus a quality scale. Serious stackers handling high-value purchases should consider a Sigma Metalytics PMV at $2,000+ for internal verification.
Final Verdict: Which Digital Precious Metal Tester Should You Buy?
After running all 8 of these testers through real-world buying scenarios, here’s how I’d recommend digital precious metal testers for different stacker profiles in 2026.
If you’re a new stacker building your first testing kit, start with the GemOro Auracle Analyzer as your electronic workhorse and the Gemtone 10K/14K/18K Testing Kit for backup acid verification. This combination covers every common scenario without breaking the budget.
If you’re a serious stacker handling meaningful volume, step up to the Auracle plus the GemOro XP500 scale for density confirmation. Add the Presidium Multi Tester III if your stack includes diamond-studded jewelry. This trio catches what most stackers miss.
If budget is your only constraint, the GTE Appraisal Kit delivers the most testing capability per dollar. At under $30 with thousands of reviews, it’s the most proven budget option on the market.
The right digital precious metal tester pays for itself the first time it catches a fake. Pick the tool that matches your buying habits, keep it calibrated, and use it on every non-sealed purchase. Your stack will thank you.