CZ Master Set 10 Stone 0.50CT E,G,I,K,M,N. Professionally color grade diamonds in seconds with GemOro's new generation Pro 2. Each stone in the precision CZ Master Set Pro 2 is treated with GemOro's proprietary ColorLast technology to ensure permanent color saturation. It is expertly hand-graded to master diamond color standards using the GIA grading scale. The set comes in GemOro's patent pending LED illuminated grading and storage case, featuring daylight and UV LEDs, powered by rechargeable NIMH batteries and a micro-USB charging/power system.