Luth-AR's MBA-1 Fixed Rifle Buttstock assembly is made to mount to an AR-15 & AR-10 rifle length A2 Round Standard Buffer Tube. It is fully ambidextrous and can be comfortably used shooting off either shoulder. The cheek piece comes pre-installed for right handed shooters but can be installed for the left handed shooter. The cheek piece not only moves up and down, it also moves back and forth on the stock. This fixed stock fits all .223 and most .308 AR style rifles. It is a constructed of super strong glass filled nylon and incorporates a castle nut and lock ring in the design. It is easy to replace and quick to install.