5" x 2" Polyon Cast Swivel Caster w/ Dual Petal Total Lock Brake - 1100 lbs. Cap.5" x 2" Polyon Cast Wheel Swivel Caster with Dual Petal Top Lock Brake Polyurethane elastomer tread chemically bonded to a cast iron core. These wheels are somewhat heavy and are ideal for warehouses with concrete and hardwood flooring. Tread: Polyurethane Elastomer Core: Cast Iron Bearing: Roller Bearing Rig: Zinc Plated Swivel Caster, 4" x 4 1 2" Mounting Plate, Dual Pedal Brake Capacity: 1,100 Lbs. Color: Green and Black Durometer: Shore A 95 (+ 5)