Hephaestus just uploaded a video showing the installation of their recently released Folding Stock Adapter for AK Airsoft guns. This stock adapter has a 6-position extension with storage compartment and is made of CNC'd aluminium. Installing this will allow you install other types of stocks such as the M4 stocks. This is suitable for GHK/LCT AK-105/AK-74M/AKS-74U series, with or without side rail.