This is a complete sionics 14.8 patrol upper reciever pinned with a surefire 3 prong flash hider. It has their extreme reduced gas port barrel. This means it will only work with baffle style silencers and since it is pinned with a surefire device it will only work with the rc2. Unless you have it repinned for something else. 


It works great, very low recoiling and reliable. Sionics built mine with a geissele mk16 rail that I sent them. Everything else is sionics parts. Asking $900 no trades.