Middle Atlantic has designed an alternative to the standard 11 gauge rackrails that are included with the MRK series of racks! The heavy-gauge, all-steel construction of the PROMRK-RR24. These rails provide a cage nut mounting option for an even, tighter, faster and safer mount. Now you can secure most any standard rackmount unit using cage nuts and rack screws (sold separately) ! Simply remove the standard rackrails and replace them with this pair of rails. Manufactured specifically for the MRK 24U racks but can be used in the VRK series as well.