The S.R.SMITH U-Frame Fullcrum Covers are of heavy-duty while extruded rubber, are 20" (508mm) in length and are formed to accept 1.90" (48.3mm) Outer Diameter tubing. The tops of these covers are grooved to reduce vibration and noise as well as to insure the most efficient board action. It is strongly recommended that this and all diving equipment be inspected at least twice per year, that this inspection includes a review of current applicable codes and guidelines and that equipment be refurbished or replaced as wear is noted.