... steel,aluminium,and most alloys.They off 1,Zirconia flap disc,with fiberglass backing padSize Arbor Grit Maxrpm Type 4 ... 12000 T27 T297” 7/8” 36# 40# 60# 80# 120# 8600 T27 T292, Aluminum Oxide flap disc,with fiberglass backing padSize ... of welds,castings and other metal fabrication application.Ideal disc for use on most metals and for wide ... grinding discs.l Suitable for Angle Grinder. flap disc 4"--7"