Sharps Bros. Handguard, M-LOK, 7, Fits AR-15 Rifles, Black SBHG08 The Sharps Bros. Full Top Rail M-LOK handguard is a one-piece free floating unit that is an attractive" functional upgrade for your AR-15. It features a full length of Picatinny top rail for the addition of backup iron sights" and M-LOK accessory mounting slots on 7 flats along its length. It includes a barrel nut and hardware for installation.