Each nylon wire wheel consists of heat resistant, nylon bristles, impregnated with abrasive grains. Shank Diameter:1/4 inch (6mm), Hex shank Use on: Power drill, die grinder, impact driver, drill press for 1/4" shank Can be used wet or dry sanding, RPM = 4,500 No sparks, Stay cool. Red (Coarse): 80 Grit, Gray(Medium): 120 Grit, Blue (Fine): 240 Grit 3" Nylon Wire Cup Brush The 3-inch Nylon Cup Brush with 1/4 inch Hex shank is designed for moderate to light stock removal on a wide array of materials, specializing in larger uneven surfaces. 3" Nylon Wire Wheel The 3-inch Nylon Wire Wheel with 1/4 inch Hex shank is designed for moderate to light stock removal on a wide array of materials, specializing precision work and jobs which require consistent brush stroke direction. 1" Nylon Wire End Brush The 1-inch Nylon Wire End Brush with 1/4 inch Hex shank is designed for moderate to light stock removal on a wide array of materials, specializing in small surfaces or confined spaces. Flexes around uneven surfaces such as nuts & bolts and compact size for hard-to-reach areas POLIWELL Nylon Filament Brush Set offers in 3 grits Red– Coarse (80 grit) for higher stock removal such as removing rust from iron. Gray – Medium (100 Grit) for more moderate stock removal such as removing heavy deposits from stone, grout and tile. Blue – Fine (220 Grit) for light cleaning and blending such as removing paint from finished woods or work on fiberglass. Attach these 3 inch nylon abrasive brushes to your drill and get to work.