kit comes with 416 Stainless Steel Barrel, 1x10 Button RH Twist, Aluminum Knurled Free Float Tube, Picatinny Rail Gas Block, Semi-Auto Bolt Carrier staked to Mil-Spec made from Carpenter 158 Steel Chrome Lined carrier Key and Carrier, Shot Peened MP Batch Tested Bolt, Choice of buttstock.and Semi Auto Lower receiver parts kit. ALL parts Made in the U.S.A.This AR-15 Rifle kit is head spaced, and ready to mount to your lower receiver. Once you have an assembled lower with the parts provided in the kit, and mount the upper, this is an operational firearm 6.8SPCII.