Fortis Manufacturing, Inc. Night Rail, Free Float Rail System, Handguard, 12, M-LOK, Fits AR15, Black NTR-12-MLOK Fortis Manufacturing's AR-15 Night Rail Free Float Handguard was designed to be easy to install and mounts to the upper receiver with 360 degrees of contact. The end result is a rail that not only looks amazing" but one that is exceptinally lightweight and robust as well. The Night Rail features a full length Picatinny top rail" shot lengths of Picatinny rail at the 3'" 6' and 9'-oclock positions and M-LOK accessory mounting slots on the side and bottom flats.