Specifications: Bristle Disc Diameter: 3/4" - 18mm Bristle Grade: Light Green - 1 mic Disc Center Hole: 1/16" - 1.56mm Reinforced Screw Mandrel: 3/32"Shank with 1/16" Screw Material: 3M Cubitron and Aluminum Oxide Grains Instructions: · For optimum results use a minimum of 3 discs ganged together, more discs can be used for wider coverage · Recommended speed from 5,000 to 15,000 RPM. · Maximum Operating Speed of 35,000 RPM · Rotation must be with the Radius of Bristles · No compounds, rouges or pastes required -Bristles contain abrasives.