Zirconium Grade Glass Fibre-Backed (For stainless steel, non-scratch). High performance alternative to sanding discs. Have the advantage over depressed centre grinding discs on light gauge sheet metal where surface finish is important. Overlapped abrasive strips slowly wear away revealing fresh abrasive, ensuring the disc always cuts effectively, reducing clogging, provides constant finish throughout disc life. No backing pads needed. Safe to use at 80m/s on any grinder. Tested at 150m/s and approved by the German Grinding Wheel Authority (DSA). Available in two grades and with two types of backing. 100mm Dia x 16mm Bore 15,300 MOS (rpm), 115mm Dia x 22mm Bore 13,300 MOS (rpm), 127mm Dia x 22mm Bore 12,000 MOS (rpm), 180mm Dia x 22mm Bore 8,600 MOS (rpm).