The Universal Bumper is a plastic dock bumper that can cover supports of many shapes. When the dock support mounts to the outside of the dock, it is risking your boat and your dock. This fender protects your dock and your boat from scratching and scraping. It fits over Dock supports like round pipe or dock jacks, or directly to your dock. Furthermore, this fender is the #1 accessory returning customers purchase and the best way to protect your marine investment. Measures 4″ wide x 21″ long x 3″ deep. Multiple mounting holes available. Bumpers that are mounted to jacks require two vinyl bolts (included) and pipe mounting requires a backer plate (included with pipe dock orders).