4" Job Box Caster Kit with Brakes Fits Greenlee, Knaack and other manufacturers Kit contains (2) Swivel with brake and (2) Rigid Casters, Mounting Hardware and Instructions Wheels are 4" x 2" Polypropylene (Plastic) with roller bearings with Brakes Contains (16) 5/16" Type F Screws for mounting Capacity: 2,000 lbs per kit