The Troy Industries SRAIDIDD7BT00, also known as Troy Drop In Battle Rails, are designed to directly replace the plastic hand guards found on all M16 and M4 carbines. Boasting a patented clamping design by Troy, these rails guarantee a sturdy mounting platform. Furthermore, the rails are rifle-length, resulting in an enhanced optical mounting platform that maximizes the accuracy and modularity of the M4. The installation of these rails is highly convenient as they require no gunsmithing and can be fitted in under two minutes. Rolled out with true U.S Military Specification M1913 rails at 12-3-6 and 9 o'clock positions, the Drop In Rail offers maximum authenticity. These rail systems are precision machined from toughened aircraft aluminum and are surfaced with Military Standard Type III hard coat along with Teflon for added durability.