This complete threaded barreled upper comes with side EZ cocker and new low Integral machined rail for optics. The side cocker makes it easier to pull back the bolt and accommodates lots of room on top of the scope rail for your optics of choice. The new low rail has a deep machined center that allows use of the iron sights. This upper for use with a M-11 9mm. Please contact us if you have any questions. (other components sold separately) Uses your bolt Fits M11 SMG and Semi Auto.