TYROLIT Sanding block disc normal corundum shape 1 straight 250 x 32 x 51 mm grain 60. Normal corundum = 10 A; for mild steel, unalloyed and low-alloy steels, dry sanding. Maximum working speed 40 m/s. Diameter (mm): 250; width (mm): 32; bore (mm): 51; grit: 60; design: straight; material: normal corundum 10A; shape: 1