LMB: MOBILE BASELMB Series base mounts inside rack frame to add mobility and a floor that's flush to bottom rack space. This mobile base adds support to extra heavy equipment mounted in the lowest rack position. Optional fine floor casters protect surfaces like wood, tile and marble. Construction is 14 gauge steel with a durable wrinkle black powder epoxy finish. To facilitate cable access, there is a center opening in the bottom and openings on the sides that match