The LMSB-22FL shallow mobile base mounts under a 22"D rack. It’s designed with casters that are positioned far to the perimeter to enhance stability of a fully-loaded 22"D rack. Construction is 14-gauge steel with a durable black wrinkle powder epoxy finish. Includes (2) 3" swivel casters in front and (2) swivel-locking casters in back. Casters have a specially formulated rubber tread that won’t mar fine floors. Each caster has a load rating of 200 lbs. (800 lbs. total for base) and raise rack height 4.33".