The Taylor Made Rigid Dock Roller Wheel is made of plastic and designed for roll-in docks and boat lifts. Wheels are manufactured from heavy-duty, roto-molded plastic with pre-drilled drain holes and feature large diameter wheels for rolling easily on all terrains. Additionally, they are designed for maximum strength with no maintenance requirements. Molded from UV stabilized polyethylene so they won’t discolor or crack. The Rigid Dock Roller Wheel is 24″ in diameter with an 8″ tread width. The Taylor Made Rigid Dock Roller Wheel fits axle sizes 1.60″ to 1.90″ in diameter. As a result, this wheel is recommended for use with Smarte Jack for boat lifts sold separately.