Our 11A2 diamond grinding wheel features man-made diamond, more consistent in shape than natural diamond, for sharp, even cutting action, durability and long life. Resin-bonded to produce a self-sharpening effect and even grit distribution. Can be used wet or dry on carbide, ceramic, glass, welds, quartz and other hard, brittle and short chipping materials. 150 grit / 100 concentration.  Measures 3.5" in diameter, has an arbor hole of 20mm and the grinding surface measures 3/8" while the diamond depth is 1/8". This 20mm hole size is used with Deckel machines.