General description Top and shank mounted router bit bearings designed for repairing road bits and creating grooves of various depths or widths in wood. This set includes high-quality steel bearings that are easy to use. Technical specifications Inner diameter: 4.76 mm Outer diameter: 12.7 mm Material: Steel Color: Black + Silver Package Contents: 20 Bearings, 20 Screws, 4 Wrenches Measurement allowed error: +/- 1-3 cm Usage Use the bearings to repair your road bits and create grooves in boards.