Diamond Tester Portable Gem Selector Gemstone Jeweler Tool Testing Kit Pen UK Description: *Turn on the power of the thermal conductivity meter, and the probe will heat up, which generally takes 20 seconds. *The hot needle contacts the surface of the sample, and it can be judged whether the signal is a diamond test sample according to the thermal conductivity of the instrument. "  Parameters: DC9V battery. (not included)  Specification: Material: Plastic Color: As shown Size: As shown  Package List: 1 x Diamond selector II tester (battery not included)  Note: Please allow slightly errors due to manual measurement and different monitors.