6" x 2" V-Groove Cast Iron Wheel Swivel Caster w/ Top Lock Brake - 1000 lbs. Capacity6" x 2" V Groove Cast Iron Wheel Swivel Caster with Top Lock Brake Cast iron v groove wheels are made for use with inverted angle track but they can also be used to roll on floor tracks, gate fence tracks and flat surfaces. Constructed of cast iron with a 90 v groove, this wheel works well inside and outdoors. Tread: Solid Cast Iron 90 V Groove Core: Solid Cast Iron Bearing: Roller Bearing Rig: Zinc plated swivel caster with top lock brake, 4 1 2" x 6