Keeps boat cover taut and free from water collecting pockets. Sockets can be mounted on any rail system or anywhere on deck wall. Rubber gasketS provides snug fit for fiberglass bows. (sockets not included: TAY-936 nylon pair or SD-327415-1 chrome plated zinc pair) Fiberglass: Flexible. Will not set when bent. May be cut to desired length. Adjustable: Two pieces held by spring clamp. Traditional Wood: Can be cut to desired length. Strong, resilient, sap-free.