Wilton Jaw Cap, Magnetic Rubber Face, For Use with: Any Vise, 4 in Jaw Width, Aluminum Alloy with Synthetic Rubber Cover. Jaw cap conforms to workpiece and grips firmly without slipping while protecting work surface. Use in combination with aluminum and Prism jaw caps to clamp taper pins or tapered workpieces. Temporary work holding systems. Designed to protect both the vise jaws and the workpiece from marring and distortion during any clamping application. Caps are constructed from a hardened aluminum alloy with two built-in circular permanent magnets on the backside which holds the product securely to the vise.