Eliminate loading on your jobs with P-graded sharp silicon carbide on the Screen-Bak Durite Q421 SC medium grits creen floor sanding disc. The excellent cutting property lets you work efficiently, and an open-weave screen offers extreme loading resistance while you remove scale, rust and corrosion. Rinse and reuse this waterproof disc to get an extended sanding life for greater value. More durable than paper and cloth, this medium grit disc handles your floor sanding jobs with ease.