Abstract: A clamp for use on a retail or commercial display device wherein a rod is slidingly received in a channel and selectively positionable therein by an position locking member. A hook plate attached to a display element, such as shelving, hanger rods, etc. has hooks for engaging a bolt mounted to the rod. A knob on the bolt is tightened to clamp the hook plate between the rod, or the post, and the inner face of the knob. The clamp may be locked in position while the hook plate is released or attached. Similarly, the hook plate may stay clamped to the display while the position lock is released, thereby permitting the clamp to be moved along the channel while the hook plate is still clamped thereto.