The Troy MRF-DI is a non-free floating direct replacement for all M4/M16 carbine plastic hand guards. The Troy Patented clamping design ensures absolute rock solid mounting which is unequalled in the world today. The MRF-DI provides a true optical mounting platform that increases the modularity and accuracy of the M4. No gunsmithing is required as the MRF-DI installs in less than a minute and provides true U.S. Military Specification M1913 rails at 12-3-6 and 9 o'clock. All MRF rail systems are machined from hardened aircraft aluminum and finished in MIL-STD Type III Hard Coat Anodize in Flat Black. Made in USA. 8.5oz Easy Install.