Attwood Light Duty Rubber Spool/Keel Roller -Road Ready spool/keel light duty rubber rollers provide protective support for your boat's hull while it's on the trailer, and allow easier launching, centering, and retrieval of the boat. Durable and protectiveMolded rubber with nylon inserts3in outside diameterNon-marring prime rubber compundEconomically priced Original equipment replacements for most trailers