The 777F coated Roloc discs contain 3M patented Cubitron mineral, which gives a faster and cooler cut. These discs are backed by heavy duty Y weight polyester giving extra strength to the Roloc. They can be easily fitted to a 4” angle grinding machine with the backup pad. They are available in sizes of 2 and 3 inches and in 36, 60, 80 and 120 grit.