The RockMaster 7" Aluminum velcro pad is designed to hold velcro backed polishing pads. The solid aluminum backer pad holder is entirely rigid and is ideal for flat surface applications. It uses 5/8-11 thread， and fits most handheld polishers and grinders. The strong Velcro face will accept all 7 inch velcro backed diamond polishing pads and scrub pads. Maximum speed should not exceed 5000 rpm.