The 7" x 7/8" Z 36X Bulk Fiber Discs (59636) from Sait are long lasting discs designed for use on stainless steel, high tensile steel, titanium, and aluminum. They are composed of premium zirconium grain with a closed coat structure for very aggressive material removal. Integrated cooling agents help prevent discoloration of materials while a resin over resin construction provides the discs with a strong bond that is resistant to heat and moisture.