? Premium ceramic and aluminum oxide abrasive grain for aggressive cutting and longer life ? New heavy cotton backing designed for superior wear resistance ? Extra fine for metal finishing and polishing ? Wheels are designed with the steel shank as an integral part of each wheel for better balance and quick changes on air tools that have a collet design ? Due to the flap wheel design and the flexibility of the material, flap wheels leave a finer finish grit that other coated abrasive products ? Flap wheels are an ideal choice for a wide variety of blending, deburring and finishing applications common in the metal fabrication, welding and polishing industries. Flap wheels are conformable to intricate shapes and contours. Designed to deliver a consistent finish with a uniform rate of cut, flap wheels wear away, continually exposing fresh abrasives.