6" x 2" Ductile Steel Wheel Swivel Caster - 1250 lbs. Capacity6" x 2" Ductile Steel Wheel Swivel Caster The Ductile Steel wheel provides extreme weight capacity for its size. The ductile steel is graphite rich, which is stronger and more durable than even our standard semi steel wheels. With a tensile strength of 45,000 PSI, you'll be hard pressed to find a job that needs a stronger wheel. Tread & Core: Solid Cast Ductile Steel Bearing: Roller Bearing Rig: Zinc Plated Swivel Caster, 4" x 4 1 2" Mounting Plate