GP12632 Rotary Hook and Loop Backing Pad with 5/8''-11 Thread, Backer Pad for Sanding and Polishing/Diameter 4 inch Diameter: 4 inch Thread Size : 5/8''-11 25mm EVA rigid layer makes this pad excellent for high speed polishing or sanding Hook and Loop Fastener (velcro type) Max RPM: 12200