FightLite DFX, Drop-On Upper Receiver Group, 223 Remington/5.56 NATO, 16.25" Barrel, Fits AR15 Lower Receivers, Gas-Piston & Pusher-Rod System, Closed Bolt, Black, Accepts STANAG Pattern Magazines, Belt-Fed M27 Links, and 100/200 Round SAW Drums, Includes (100)-M27 Links DFX-001