FOR USED PLATENS. Horizontal Clamp. Clamping HEIGHT of 2 inch (with sliding arm reversed) to 15 inch. Throw of screw: 3-1/2 inch. Round Knurled boot fits 1-5/8″ square hole typical of some old, used Platens. Simply drop this clamp into a square hole, and it is ready to go. Clamp WILL tilt back as it makes contact with work piece. Clamping in all radial directions. Very simple and very fast clamping (and unclamping).