5KU Threaded Tornado Aluminium Outer Barrel - 5.1 - Black
The new Tornado outer barrels for the 5.1 - A first for the UK!
These will accommodate a tracer or mock suppressor with its 11mm internal thread.
If you're going for looks, a CowCow Thread Adapter looks sweet on these to (allows for longer inner barrel to be used also...boosting your FPS)
Non-drop and regarded as one of the best upgrades for your capa.
* These are a tight fit, which is great news (Less inner barrel wobble) O-Rings not really needed.