The WoodRiver® 4-Way Clamping System applies equal pressure from all four directions (top, bottom, and both sides). The ideal clamping system for gluing table tops, shelving, veneer, and laminates. This clamping system uses plastic pressure pads and two 19-1/2" tough plastic tail bars with 12 notches to handle a variety of stock widths. It can be used on boards up to 6" thick. Attach the clamps to any length 2 x 2's with the screws provided, set the jig and turn the handle to tighten (on large pieces, position every 12"- 18" for maximum clamping efficiency).