Scotch-Brite(TM) Finishing Flap Brush Steel, 12 in x 50 in x 5.75 in 5S SFN, 1 per case, Custom Light duty for cleaning and finishing applications. Individual sheets adhered at a 90 degree angle to a steel core. Medium hardness 5 density. Abrasive mineral: Super fine grade silicon carbide. Color: Gray MOS: 1800 RPM