Made from a non-woven synthetic fiber mesh impregnated with abrasive grain. Open structure prevents loading. Will not rust or contaminate metal. Waterproof, washable, use wet or dry. General Purpose, medium density-5A (Red), blends belt marks, removes rust and surface oxidation, finishes and deburrs. Produces a clean uniform surface, blends surface scratches and produces a satin finish. Light Deburring, fine density-7S (Gray), tough and aggressive, durable yet resilient and fast cutting. Produces a bright finish on hard surfaces, such as stainless and titanium. Flap Wheels, fine density, for final sanding/finishing on wood or metal. May require arbor adapters to reduce. Size and adapters shown in description. Maximum rpm 4500. Use with arbor reducers WA312 (3" with 1/2" arbor), WA358 (3" with 5/8" arbor) or WA334 (3" with 3/4" arbor).