Swivel Caster V-Groove Forged Steel Wheel Tapered Roller Bearings in the Wheel. Shown in Photo with 8″ x 4″ Wheel. The V-Groove swivel casters require a Swivel Lock in order to go backwards when on Angle Iron Track. The Swivel Lock and the Wheel Brake Options may add 1 week to the lead time. They are not returnable if ordered with either option..