Time-saving and practical, RIB Series riser bases are 2-1/2" high risers which provide the ability to perform field rough-in procedures prior to the arrival of the racks and enclosures. Handy as lower cable chase for passing cables between racks in multi-bay applications, RIB riser bases feature 1/8" thick fully welded construction and an attractive black powder coat finish. 4 Bays. Accomodates: MRK/VRK/VMRK 31" depth racks.