A quick and easy way to create a on location lighting grid. Cut wood 2"x4" to proper length. End cup (non adjusting) mounts on one end of 2x4 and the Adjustable End Cub mounts on the other end. End cups must press against wall studs, then just turn adjuster to expand an put pressure against wall studs. Wall Spreader should be properly secured with back up safety cables or chains before mounting lights.