Firepower Knotted End Brush Steel 0.25-in Grinding Wheel1 4 In. shank, 0. 020 In. wire size, 20,000 max RPM Designed for use in restricted or hard to reach areas, end brushes are great for cylinder heads, pistons and valve ports, rubber and plastic flash removal, removal of rust, paint scale, tool polishing, and weld cleaning Excellent for debarring, blending and cleaning of surfaces Small diameter brushes are especially designed for use on portable air and electric tools Features Sub Brand N A Series Name