Flap Rolls have a wide profile (up to 4") which makes them an ideal accessory for finishing large surface areas with protable finishing tools*. their rotation provides a grained, or linear surface finish, as opposed to the swirl pattern produced by discs. Common applications include stainless steel panels, cabinets and food preparation equipment. All Alpha Industrial Flap Rolls have a quad-keyway design to prevent slipping and fit nearly all keyed spindles.