The Geissele MK16 M-LOK Super Modular Rail in Black (05-1073B) 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 not rotate, even under the most extreme conditions of use. M1913 Picatinny rail on top and M-LOK™ slots on every quadrant ensure 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.