1. Use: diamond grinding wheel for precision machining of glass: glass thickness, jade, jade, agate, pearls and other building materials.2. the correct use method: electric drill speed 3600 rpm, bench drill and machine speed in 6000 - 10000. The water must be polished so as to achieve the best effect.3. About how to choose the explanation: if the material thickness of 8mm, choose the appropriate 8mm diamond grinding wheel.Specification:Shaft diameter: 6mmOuter diameter: 20mmGrit:150Width: 5mmColour: As ShownMaterial: electroplating emeryPackage Contents:1 x Diamond grinding wheelOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 1-3cm.