The Rail Mounted Fixed Loop (RMFL) allows a quiet, secure sling mounting loop to railed forends. Machined from aluminum and hard coat anodized, the RMFL provides a solid and silent sling loop on MilSpec 1913 hand guard rails (may require minor fitting on others).To install, slide loop down the rail (screw entrance side up) to desired position, insert the provided flat head screw, and tighten with any multi-tool with a flat blade screw driver (instead of odd hex head bits that get lost). As with all Blue Force Gear, it is made with excellence in the USA and carries a limited lifetime warranty.