Features: Diamond indicator will be showed if the stone is a REAL diamond (Green light). Metal alert (continuous buzzing sound when user accidentally touches metal rather than stone). Large / small switch for testing diamonds / - 8 points. LCD display & LED indicator. Powered by DC 9V battery x 1 ( Included) How To Test Diamond Turn on the switch. Make sure only 1 light is lighting up on the scale. Wait few seconds for the probe to heat up until Lamp on ready OK. Turn on the lights numbers corresponding to the indoor temperature and diamond weight. If don't know. Set 4 lights is lighting up on the scale. Start test diamond, no need to adjust the switch switch. Use the diamond discriminator probe to make 90-degree contact with the measured object, and observe the indicator light change. It needs a little bit of force to stop it on the diamond surface and make full contact. If unsuccessful, please repeat the second step. Yhkj Diamond Tester Pen Test result analysis If lights >= 9 and have sounds, it is true diamond. If lights