||Use this two piece clamp to mount rod holders onto your boat rails. Fits popular rail sizes on Alumaweld and Willie Boats. Our clamp allows you to easily move and slide your rod holder along your rail, and does not require holes drilled in your boat. The clamp features a threaded hole and thumb screw (included) to keep the rod holder locked in the desired position along the rail. Photos show the clamp installed with a Scotty base and holder (not included) and the clamp also works with Folbe and FishOn! bases, Fits rail up to 1 3/8" thick by 2 3/8" tall.