3M™ Cubitron™ II Roloc™ fiber discs 786C is built for grinding, weld blending, deburring and other tough metal finishing jobs. 3M™ precision shaped Grain - a tough, hard, sharp ceramic abrasive - is resin bonded to a stiff fiber backing. This disc lasts significantly longer than conventional ceramic grain discs, delivering a lower cost per grind with fewer disc changes.