LCT Airsoft has been releasing parts for its airsoft guns to allow players to modify them that suits their taste. In this video they show you how to install the LCT Airsoft PK340 Stock Tube which then will allow you to install different types of buttstock ranging from the usual M4 stock to the Magpul CTR. AEG in the video is the LCT PP-19-01 Vityaz AEG but it is compatible to other LCT Airsoft AK AEGs.

LCT Airsoft announce the new PK340 TK Folding Stock Tube that can be installed on different LCT Airsoft AEGs... "The  TK Folding Stock Tube and compatible LCK AEG which is with folding or under folding stock, ie. LCK74MN / LCKS-74M / LCK-104 / LCK-105 / LCKS-74 / LCKS-74UN / LCK-106 / TK-105 / TK-102 / TX-S74UN / PP-19-01 AEG.

And with this parts you will have more space for putting battery on stock."