Akro-Mils AWPCAST4 4-Inch Swivel Caster Pack for Chrome Wire Shelving System Upright Legs 2 Casters with Brake Create mobile wire shelving units with caster sets Includes 4 4" swivel casters, 2 with brakes, 2 without brakes Compatible with most standard wire shelving systems. Pair with Akro-Mils Chrome Wire Shelving system