4" Diamond Convex Polishing Pads Set of 8 PCS and Convex Back Holder For Concave Sinks or Ogee Edges 1 of each grit 50,100,200,400,800,1500,3000,black buff and convex back holder; Aggressive and long-lasting; Attach to Convex Back Holders only; Wet applications only; Maximum speed 4,000RPM.