GERMAN Made "COOL" DIAMOND GRINDER - Heat Resistant, Diamond Impregnated and Long Lasting.  Unique Diamond Powder selected, combined with a special binder, ensure restorations of Zircon Oxide & Lithium Disilicate to remain cool, thereby reducing the possibility of creating micro fractures while grinding. Some ceramists prefer using Coarse Grit, just slightly more abrasive, yet they also remain cool and effective.