Tools can be used on Angle grinder and pneumatic machine. Use on concrete, engineered stone and granite material. Use wet or dry. Diamond cluster points rip away epoxy and fiberglass backing. Flat tip leaves a smooth finish for easy surface preparation. Great for removing resin polish to prepare the slab for honing. New waterproof coating on all sizes feature allows for use in wet grinding applications. Can be used effectively for fast edge shaping applications. Excellent light weight wheel for air polishers. 5-8" - 11 thread. 15,300 MAX RPM.