Cutting Head is 3/8" diameter X 3/16" long. Saburr-Tooth burs are fast cutting, long lasting tools designed to work easily and efficiently. Saburr-Tooth burs feature a fast cutting patented carbide coating that is designed to cut cleanly on most materials. They will not load on most materials and are extremely sharp and are very controllable. They are designed for use in tools with speeds of 4000 RPM to 19000 RPM.