ScreenBak Durite Q421 fine grit screen sheets are a great choice for efficiently sanding and finishing fiberglass and composites, aluminum, brass, bronze, titanium and super alloys, hard, soft and 300 Series stainless steels and hard and soft woods Engineered with a Pgrade silicon carbide abrasive, these open weave screen sheets deliver excellent cutting and remove scale, rust and corrosion with minimal loading They’re waterproof, so rinse and reuse them for final sanding applications and light material removal They’re packaged in a handy protective dispenser to reduce waste and make storage simple