The Super Modular Rail 13.5″ (SMR) MK16 M-LOK®, NSN# 1005-01-672-4794 (13.5”), has been adopted by USASOC for the URG-I program (Upper Receiver Group Improved). The Geissele Super Modular Rail MK16 offers unmatched performance for the most demanding shooters. Mounted to your AR-15 upper using the updated version of the proven Geissele Barrel Nut design, the MK16 is not only easy to install and maintain, but offers superior rigidity. Anti-rotation tabs and set-screws ensure that your rail will won’t rotate, even under the most extreme conditions of use. M1913 picatinny rail on top and M-LOK™ slots on every quadrant ensures maximum customization for all your accessories. The Geissele SMR MK16 is precision machined using 6061-T6 Aluminum due to its strong, rigid and light properties, and is finished in durable Type-3 Hardcoat anodized. A 9.3″ variant of the MK16 is also available for users requiring a shorter platform.