Intuitive Design: Diamond Tester Pen comes with LED lights and audio indication. Once our Tester Pen has completed all of its tests, the pen will make a beep sound as well as show a row of fully lit LED lights Simple to Use: Diamond Tester Pen is simple to operate to get results, professional(s) are not required. Simply turn on our Diamond Tester Pen detector; place the tip of the Diamond Tester on the gem stone (lightly pressed is sufficient) and if the stone is fake, crystal or cubic zirconia, the tester will not beep Application: Used for industrial purposes, circuit board and printing, industry, medicine, gardening, coin, diamond, stamp, jewelry, appraisal, education, geography Specification: Item: Diamond Tester Material: metal, plastic Size: 160*40*22mm Display: LCD and LED indicators Power: DC 9V battery x 1 (not included) How To Use: 1. The power indicator lights up, and the preheating starts. 2. Place the diamond on the plate with the table top facing up. The already set diamonds are held by hand. 3. Move the LED indicator according to the weight of the test diamond and where the temperature is measured. 4. Remove the needle cover, hold the instrument, and touch the conductive plate on the back cover of the instrument with the right index finger. Touch the probe vertically and lightly to the diamond. 5. Observe the instrument carefully, if the rest of the lights are yellow, when the light position moves to nine lights with a beep, it means it is a real diamond. Conversely, if the LED lights move to less than nine lights and there is no beeping sound, it is a fake diamond or counterfeit.