6X2 Heavy Duty Caster Steel Cast Iron Wheel – Industrial Caster Wheels, Set of 4 with up to 5000 LB Capacity – Widely use for, Tool Box and Workbench (4 Swivel). CASTER FEATURE: The Steel casters contain a Stong Roller bearing, and steel Spanner Bushing, rotated 360 degrees smoothly, and quietly; Zerk Axle and Nylon nut make the caster tight, not easy to lose and also can be used on any floor condition, and service for a long life.