Norton Metal R828 coarse and extra coarse grit 5/8-11 arbor fiberglass backed heavy duty conical flap discs. This disc features lightweight fiberglass and resin backing plates, while a zirconia grain delivers excellent cutting action on stainless, cast iron, titanium, and super alloys. A great option for quickly blending and deburring, this disc includes angled polyester and cotton flaps ideal for sanding edges and contouring work.