The Yost Vises MR-340 4" magnetic aluminum vise jaw caps with rubber surface attach to and cover a set of 4"-wide serrated vise jaws to shield delicate work from damage. The caps are made of aluminum for durability and have a rubber finish that prevents the clamped item from being marred. The magnetic backing runs the full length of the cap to securely bond it to the front of the vise jaw. Two jaw caps are included.

Yost Vises manufactures a wide range of vises, including bench-mount, woodworking, and drill-press styles. The company, founded in 1908, is headquartered in Holland, MI.