Clamps over the frame of a 1911 Auto to provide a solid guide for getting the front strap checkering lines started correctly. Sets up 60deg or 90deg diamonds. Long enough to allow a good, long, contour-following stroke on the Checkering File. Mfg: Brownells SPECS: 2 1/2" (6.3cm) long, 1" (2.5cm) wide. 7/16" (11.1mm) thick. Aluminum Guide and Clamp Bar. Allen head Lock Screw.