TROY Industries Picatinny Rail Top Gas Tube, Fits AK-47, 5, Black Finish SRAI-AK1-T0BT-00 The railed gas tube will fit all (stamped and milled receiver) AK rifles with a standard length gas tube. Length is adjustable for variation between rifle manufacturers. May not fit all AK variants" Any modification to product will void all warranty. The 5 inches of Picatinny rail provides space to mount optics and accessories. The low profile of the rail allows lower 1/3 co-witness with some optics. The Railed Gas Tube will work with factory hand guard" independent of the Short and Long Bottom Rails. Replaces factory gas tube easily; no gunsmithing required. Machined from hardened aircraft aluminum and finished in MIL-SPEC hardcoat anodizing. Attach optics and accessories to the Picatinny Rail.