The DEWALT DARB1G0805 4.5-Inch AO Fiber Resin Disc 80G features high performance aluminum oxide grain which allows the disc to break down quickly, consistently exposing new grain for faster removal. Aproprietary material mix ensures durable long life discs, and a tough fiber backing prevents tearing. 5/8"11 arbor discs use quick lock backing pads for quick disc changing.