The R16M4FTT is Windham's flat-top, M4-profile carbine with a free-float triangular handguard and a two-stage trigger. The FTT designation indicates flat-top receiver with Troy folding sights and a two-stage trigger upgrade over the standard SRC. Type: Semi-Auto Rifle Action: Gas-Operated Caliber: 5.56x45mm Capacity: 30 Year introduced: 2012, USA Weight: 7 oz Overall length: 32.6" Status: Active Intended use: Range, Patrol, Precision