The Daniel Defense M4 Rail 7.0 Free Float Rail System is the lightest rail system available on the market, bar none! It weighs an astonishing 8.5 Ozs. (including the threaded ring, barrel nut and indexing pins) but is as sturdy as similar designs weighing twice as much! The Daniel Defense M4 Rail allows the individual operator to mount M4 and AR15 weapon accessories to this Military Specification 1913 Free Float rail system increasing the combat effectiveness of the weapon immensely. The Free Float design of the M4 Rail allows the barrel of the weapon to operate free from accessories mounted to the rail system. This is advantageous to the operator because so the operator will experience no degradation in accuracy with added accessory weight impeding proper repeatable barrel harmonics.