For clamping corners for a secure bolt down clamping tool. Works great with WSCORNER12 or two WSTOWER12, WSTOMB12, or two WS31C Angle Plates. Clamp fits Weldsale Platens with typical 1-3/4 in. square holes. Will clamp at Platen surface or up to about 5 inches above the Platen surface (with proper support).