Command Arms Accessories/EMA Tactical is proud to announce their M4S1 M16/AR-15 Carbine Handguard System which sets the standard for a stable and rigid design by combining interlocking top and bottom handguard sections with a bottom rail that can be mounted to the existing sling swivel mount for absolute rigidity. The M4S1 handguard will not move once locked in place providing repeatable zero. This is the first lightweight polymer handguard designed to withstand the extreme operating temperatures of a gas piston system. This extreme heat resistance is achieved by manufacturing the M4S1 from a proprietary heat resistant polymer, including a heat shield and providing significant upper and lower handguard venting in the design. The M4S1 also works with standard direct gas operating systems. The M4S1 includes two interchangeable lower rails of 4 inch and 1.75 inch lengths. This allows the operator to quickly change rails based on mission need. The two 1.75-inch side rails are removable if not required. Even with the side rails attached there is enough room left on the contoured handguard for your hand to hold it comfortably. An optional 9 inch long aluminum top rail attaches to the handguard and flat top rail providing a super stable platform for mounting optics and sights. The M4S1 also includes two mounting points for a push button quick detach sling swivel. www.commandarms.com.