This Bolt-down Kit is for the 18, 24 and 38U Netshelter CX product set. Of the 2 brackets in this set, one L-bracket affixes to the underside of the CX to pre-existing bolts. The other L-bracket affixes to the floor. Design is such that the 2 brackets can be fixed to the CX and floor first, and then the CX can be wheeled into place to secure the enclosure to the floor. Connection between the 2 brackets can be made using the nut < bolt hardware included, or by using a locking mechanism (not provided).