Diamond selector II, original Japanese tester by CULTI

Summary By far the best of the 'cheapie' diamond testers, original Culti Diamond Selector II, made in Japan, not a Chinese copy. What's the difference? - see the article, Diamond Selector II testers - genuine or fake? Of the many identical-looking testers this is the original and the best quality (best build-quality, best reliability) Standard format, nearly everyone who has used a diamond tester is familiar with how to use this one Adjustable sensitivity, so you can (within limits) use it in cold conditions It does not test for Moissanite (a manmade stone that is not diamond) - Moissanite shows up as diamond on this tester. Guarantee: 1 year See also, everything you need to know about testing diamonds in the Guide to buying diamond testers.  Operation Turn it on, wait about 30 seconds for it to warm up, carefully set the sensitivity according to the chart on the tester, place tip in the centre of the stone, note how high (and at what speed) the LEDs light up. Technical PHYSICAL Size: 6¼"X1½"X¾" 155X38X20mm Weight: 105g Tests stones down to 0.03ct (3pt) in size Operating temperature: recommended between 18 and 27 degrees C (64 to 81 degrees F) but you can use it in cold conditions if you turn the sensitivity down relative to the size of stone (there is a chart of numbers on the tester to help you work this out). RESPONSE TIME Warm-up time about 30 seconds Testing time 2 or 3 seconds    Warm-up time between tests anywhere from 3 to 8 seconds depending on the temperature POWER Power: one PP3 battery (supplied) Battery life: un-tested, but certainly a few hundred tests Auto-shut-off: none, i.e. if you forget to turn it off the battery goes flat Low-battery indicator: none, when the lights fade or flash - change the battery.  ACCESSORIES / PRESENTATION Vinyl carrying case Stone-holder Well-written instructions RELIABILITY I haven't tested this on thousands of stones but I estimate that you would get a correct result 80% to 90% of the time (excluding Moissanite, which will always show up as diamond). Developed a fault in the guarantee period (1 year): 3% Disclaimer All equipment and materials must be used in conjunction with the user's skill, knowledge and experience. Under no circumstances shall QUICKTEST be liable for direct or indirect loss sustained in connection with any item. It is your responsibility to regularly check equipment against known samples, to ensure that it is working correctly.