4 in. Polyurethane Fixed Caster with 375 lbs. Load RatingEasiest rolling, heavy duty, 375 lb. capacity 4 in. fixed caster with standard size 2 3 8 in. x 3 5 8 in. slotted plate. This caster features ball bearing construction, non marking sold polyurethane wheels, a 1 1 8 in. W tread, and an overall caster height of 5 in. It is the perfect replacement caster for any standard wood dolly and especially the SNAP LOC Dolly. 4 in. fixed caster with standard size 2 3 8 in. x 3 5 8 in. slotted plate Easy rolling