This is one of our classic AR15 pistol upper receivers. 5.56 caliber; full quad rail handguard with nitrided barrel that you can beat up and it just keeps going. Also backed by our 100% guarantee that you will love it. With all the KeyMod and M-LOK handguards out there this is still one of the most popular uppers we make. A complete classic look to it that just runs great has an AR15 pistol or SBR. Purchased one today and you will not be disappointed. And we ship same or next business day and can customize anything you want here at Veriforce Tactical.