Finally, an easy solution to mooring your boat to a pier. No more struggling to tie the boat off as it drifts away. Simply slip the ZipDock over the pier post, pull rope to quickly adjust the distance from the pier, and ZipDock locks the rope in place securing your boat to the pier. The ZipDock has an integrated self-locking mechanism with quick-release lever that eliminates the need for knots. Rugged, UV-resistant polymer construction. Comes with braided 8' x 3/8" polypropylene rope with cleat loop. Fits most standard and decorative pier posts up to 4" in diameter.