This device is easy to set up and reduces the need for multiple clamps. The machined aluminium caul is 5-7/8" long and 1" wide, and has a slightly arched bottom to accommodate most bridges on flattop steel-string acoustic guitars. It's padded with thick cork on the underside and on the thumbscrew-adjustable end clamps. It's a good idea to use it with bridge pin inserts to prevent the bridge sliding around as the clamps are tightened. This one has been used a few times in our workshop. Some clamping marks to the top, but otherwise in 'as new' condition.