These hook clamps are designed to move up and down in conjunction with the tightening screw. They are actuated in both directions with the hex screw on top of the clamp to prevent galling of the workpiece. These clamps are ideal for applications where space is limited. The flanged holder provides a low profile as well as easy installation and operation of the hook clamps. The clamp body is made from 1045 alloy steel, quenched and tempered, with a black oxide finish. The holder is made from 1045 steel, quenched and tempered, with a black oxide finish.