The M400 TREAD features a free-floating M-LOK enhanced handguard that is lightweight yet rigid for extreme control and ease of mounting accessories such as lights and handstops. The lower receiver has an ambidextrous safety for right or left-handed operation and includes an integrated QD mount for easy sling attachment. Chambered in 5.56 NATO, the M400 TREAD has a 16? stainless steel barrel offering extreme durability and corrosion resistance while improving accuracy. The barrel is also fitted with a 3-prong flash hider and has an extremely versatile 1:8 twist rate. The M400 TREAD also has a mid-length gas system offering smoother operation and reduced recoil. The new M400 TREAD includes a SIG Matchlite 2-stage trigger for enhanced control and improved accuracy as well as a MAGPUL SL-K telescoping stock for easy adjustment and a customized fit. The new M400 TREAD. All of the freedom, all of the features, with none of the compromises. Sig M400 Tread AR-15 Rifle, .223 Remington/5.56 NATO, 16." Barrel, Magpul SLK Black Stock, Black Finish, 30 Rds