This AR-15 Carbine length kit comes with our standard A-3 flat-top upper With M4 Feed Ramps, lower parts kit, and your choice of A-2 Buttstock or CAR stock (pictured). Available with HBAR or Light Weight contour barrel. This kit comes with a 16" barrel, 1x9 twist, completely assembled to our A-3 flat top upper receiver, the lower parts kit for your stripped lower receiver, and choice of A-2 (standard length) or 6 position buttstock and is everything you need to assemble your stripped lower receiver into a functioning AR-15 rifle.