My mistake. a5. I haven't done a full teardown yet but it has a neckpiece that makes putting on my large metal ris from my marui mp5 impossible. For now.
The battery is in the foregrip. Holds a small. Pretty slick system. It allows for a very slim ris and holds together well.
U.S cost on these is around $160-80. They are new so some places may not have them yet.
I have a friend who is willing to get them here for a price.
In Canada cost will be around $330. They are on order. I got the last one.
For other JG stuff, check my post in the for sale forum
Grand Poobah of T.W.A.T.