Square Bearing 12.7mm OD x 4.8mm ID

The square bearing stops spinning as soon as it touches the workpiece. Then, the side of the square simply slides along the workpiece edge. Compare this to a regular bearing that rolls along the edge- building up glue and residue with every revolution. Plus, the square is made from a non-stick material, so it wipes clean easily, and it won't mark your workpiece. Outside Diameter: 12.7mm Internal Diameter: 4.8mm