"This Wel-Bilt 4-Pk. of 3in. Casters allows you to easily convert a stationary wire shelf unit to a mobile shelf unit. Works with all sizes of Wel-Bilt wire shelving. Casters qty. 4, Threads per Inch 3/8-16, Wheel Diameter in. 3, Capacity lbs. 300, Caster Type Swivel w/brake. Not related to WELBILT products of Enodis companies 300-lb. capacity per set of 4"