AR-15 Stock Completion Kit
Buffer Tube Assembly for A2/A1/M16 Style Buttstock
All the components needed to mount the non-collapsible styles of AR-15 buttstock such as the Magpul PRS and Choate E-2. All parts are manufactured from the highest quality materials and held to strict dimensional tolerances for proper fit and function.
This is the A1 buffer tube with an A2 spacer. So, it will fit either A1 or A2 stock installations. Basically, the military M16 non collapsible stock system. This is the system used by the Magpul PRS stock and the Choate E-2 stock.