Foam-backed straight diamond hand pads are for use on granite, marble, concrete, glass edges and surfaces. One whole set has 8 grits, from rough grinding to final honing: 30, 60, 120, 200, 400, 800, 1500, 3000 grit. 30 grit - 400 grit pads are electroplated; 800 grit - 3000 grit pads are resin bond.