The sintered diamond head of these rotary burs are made up completely of a diamond matrix. Ideal for cutting hard material, lasts MUCH longer than a standard plated diamond bur. These Diamond Bits are designed for aggressive and faster grinding for higher productivity and time saving Extremely durable, long lasting and economical. - Glass, Jewelry, Lapidary & Lab Sintered Diamond Bur HP Shank - Diamond rotary instrument for precision work - Ideal deterioration and finishing of surface applications