Flap wheels are ideal for contour sanding. A&h Abrasives™ aluminum oxide mounted and unmounted flap wheels are well suited for deburring, scale removal, cleaning and surface preparaction on ferrous and non-ferrous metals, plastics, rubber and wood: Mounted flap wheels have a 1/4" shank allowing mounting on a 1/4" or larger chuck - ideal for high rpm die grinders, air tools, drill motors and other portable and stationary power tools. Unmounted flap wheels are best for a uniform finish on contoured parts (metal, plastic, wood) - use with portable air tools, electric tools and bench grinders. USA.