Something at SKDTac which you can use in sprucing up your M4 Gas Blow Back Rifles or Systema M4 PTWs... "TROY TRX (Troy Receiver Extension) BattleRails are a One-Piece Free Floating Rail, designed for secure installation. Troy TRX rails are custom manufactured from aircraft aluminum and finished in MIL-SPEC Type III hard coat with Teflon.  The lightest-strongest-sleekest, free-floating rail available!

Features

• New state of the art rotary locking system
• Proprietary patent pending one-piece design
• Continuous, uninterrupted top rail
• Reduced heat transfer
• Significant weight reduction
• True U.S. Military Specification M1913 rails
• Increases target acquisition speed
• Free floating design that enhances accuracy
• TRX Extreme also includes one 4” and two 3” quick-attach rails for accessories
• Includes Troy barrel nut
• (Actual length: 7.6")"