Quick change flap wheels have a threaded shaft that fits mandrel #93496. Wheels simply spin on/off for easy & quick changing if the operator needs to move to another grit to finish the job or if the wheel is worn. Flap Wheels are used for blending and finishing all types of steel, stainless steel, aluminum and other non ferrous as well as plastics, acrylics and wood. All flap wheels are made of PREMIUM German produced aluminum oxide resin bond cloth for a controlled cut and uniform finish throughout the entire life of the wheel. Flap wheels are used for quick stock removal, light deburring, cleaning welds, removing rust and other surface imperfections.