Why you need this tester Fast, reliable way to check diamonds, moissanite and common simulants at home or in a workshop. Removes guesswork: audible tone and digital readout tell you whether a stone conducts heat like a real diamond. Works for both beginners and professionals — no special training required. Key benefits Easy to use: power on, touch the probe to the gemstone, wait for the beep and LED reading. A real diamond lights up to 9 and produces an audible sound. No reaction indicates a fake or common simulant such as cubic zirconia (CZ). Thermalconductivity testing: distinguishes real diamonds and moissanite from many fakes by measuring heat transfer through the stone. Adjustable for different sizes: set the tester for the approximate carat size shown on the screen to improve accuracy. For stones over 1.0 carat, turn on one green light; for 0.5 carat, turn on two lights; for smaller stones use three to four lights. Quick feedback: audible frequency tone and visual readout give clear, immediate results so you can test many stones efficiently. Portable, USBpowered: powered via the supplied USB cable for testing anywhere you work. What's included 1 diamond tester pen (probe + display) 1 USB cable for power 1 testing platform 1 user manual How it solves common problems Eliminates uncertainty when buying, selling or repairing jewelry by giving a quick, objective test for diamond authenticity. Reduces the need to send stones to a lab for an initial screening, saving time and costs. Helps hobbyists, estate buyers and retail staff spot common simulants like CZ and detect moissanite versus diamond. Practical use scenarios Retail or pawn : screen incoming inventory quickly before deeper appraisal. Estate or online purchases: verify stones received match the seller's description before final payment. Home jeweler or hobbyist: check heirloom pieces, work, or items found at estate sales and auctions. How to use (simple steps) 1. Charge or connect the tester with the supplied USB cable. 2. Power on the device and select the caratsize setting shown on the screen. 3. Place the stone on the testing platform if needed, then press the probe tip gently to the gemstone. 4. Listen for the audible tone and read the LED/display. A real diamond lights up to 9 and emits a sound. No reaction indicates a likely simulant. Important testing notes Do not test on metal, skin, or in water. Metals and some simulants can produce frequency sounds or misleading results because of similar thermalconductivity behavior. Follow the user manual for probe contact pressure and caratsetting guidance to ensure consistent results. Reliable, straightforward, and portable — this diamond tester pen kit gives clear thermalconductivity testing for diamonds, moissanite and common simulants, with the accessories you need to start testing immediately.