A ceramic and aluminum oxide abrasive grain structure superior in performance and life to the standard green silicon carbide stones widely used in dental labs today. Use them for cutting and polishing work on all metals you are now finishing with silicon carbide stones. Dress porcelain pieces between firings with less chance of thermal damage. They remove material faster yet run cooler...and last 3-5 times longer than silicon carbide stones. CeramCut Blue Stones have 3/32 (2.35mm) shanks and overall length of approximately 13/4.- 2. depending on head length. Dimensions are nominal and slight variations may exist. Rated for use at speeds up to 45,000 RPM.