Used to measure the distance between points that are too great to be reached with dividers. The heads are die cast and have hardened, forged steel divider points. The points screw into the heads, and the pencil socket accompanying each set of trammel heads can be used in place of either point. Die cast heads with black wrinkle finish. Heads accommodate a beam (not supplied) up to 3/8 in thick and 3/4 in wide.