Designed with a special bond for large format Porcelain and Ultra Compact Surfaces. For best performance use at 5,000 RPM with center water feed. For use on Porcelain, Ultra Compact Surfaces, Granite, and Marble. Use wet or dry. Usable length 2" on sizes 5/16" and 1/4". Usable length is 2.75" on all other sizes. Max RPM 5,000