"Designed to fit directly onto your polishing machine with an M14 thread.Metal Bonded diamond, aluminium backed to make them light weight and easier to use. Use wet or dry for rapid stock removal on all types of hard or soft stone, concrete or masonry.Three grades available with a recommended working speed of 3000 to 4000 rpm.1. Full ranges of specification, Custom-made is available.2. Never mark the workpiece an burns the surface of workpiece 3. Good balance assures exnt grinding effect4. Long lifetime and stable performance "