4" x 2" Swivel Caster Polyurethane on Steel Hub w/Top Lock Brake 700 lbs. Each 4" x 2" Swivel Caster Polyurethane on Steel Hub w/ Top Lock Brake 700 lbs. Each Feature: 3/4" Roller Bearing with 1/2" ID Bushing (Manufacture will provide zerk fitting in the wheel or axle) Bearing: Roller Bearing Capacity: 700lbs Material: Polyurethane on Steel Hub