Geissele Automatics 05190B Super Modular Rail HK Black Aluminum 10.50" LongThe Geissele Super Modular HK 416 rail was designed to replace the standard rail on the HK 416 weapon platform. Constructed of precision machined, 6061 T6 aluminum allows the SMR HK to incorporate strength, rigidity and modularity while utilizing the stock HK barrel nut. Finished in Type 3 Hardcoat Anodize to meet military specifications and able to use rail sections at the 3, 6 and 9 oclock positions to mount accessory rails, using steel inserts for