The Neiko 11108A 80 grit Aluminum Oxide 4.5” Flap Disc is a T27 flat disc outfitted with a 7/8” arbor and are packed in a 10-piece set. Flap discs are a multi-functional abrasive which can perform stock removal and surface finishing at the same time. These AO flapper wheels are best used on ferrous and non-ferrous metals like stainless steel, carbon steel, tool steel, nickel alloy, aluminum, titanium, cast iron and welds. AO flap discs can be used on other materials like rubber, plastic, fiberglass, and wood, but Zirconia would be a good alternative if longer life, faster cut, and higher heat and pressure are concerns. Abrasive flap discs are commonly used in welding, machining, manufacturing, heavy-duty equipment work, and industrial maintenance. Can be used to remove paint and rust, cleaning flashing, edge grinding and chamfering, deburring, blending of weld seams and materials, stock removal, sharpening, shaping, contouring, and smoothing of various materials, surface preparation and surface finishing, and the finer grits can be used for shining and polishing. Choose coarse 40 grit when removing more material or initial grinding, flattening, or shaping. Choose medium 60 or 80 grit for surface preparation, cleaning, and deburring. Choose fine 120 grit for blending or creating a semi-polished surface.