Review and gameplay video by VOC Airsoft featuring tthe Poseidon Stormbreaka CNC HPA adapter... "The Poseidon Stormbreaka adapter is a CNC aluminium HPA adapter which features a variety of colours. This gives you the option of using M4 AEG magazines with your pistols.

It also has the option of swapping between Hi-capa or G-series magazines

You can purchase this adapter from Poseidon directly, or if you are in HK you can check out promo shop."