The Dock Floats Ltd. Dock Wheels are molded with thick marine grade vinyl to with-stand rough treatment and harsh marine conditions.  The wheels have a molded-in hub and axle, so there are no metal to metal fittings to rust or corrode.  This unique design ensures years of trouble free use and aids the boater while maneuvering in and out of the slip.  All of the wheels are factory inflated so they never go flat.  The rings of holes around our dock wheels offer much more protection and cushion than a single wall dock wheel.