One of the biggest problems with the G36 series is lack of a storage spot for a large type battery. This stock, from the G36KV, allows for storage of a large type battery in the stock, while still allowing folding and adding a bit of retraction should the user need some adjustment. Cost me $65.00 usd from UNCompany, arrived in 5 days with other parts.
The stock is a reasonable, but not exact, copy of the HK "V" stock. It's really only missing the "HK" trades on the sides and a few details, which in ABS plastic, may cause some weak spots. Same fit & finish as their G36KE folding stock & carry handle with 3.5X scope, which means it doesn't quite match the TM plastic, but we're used to that. Comes with the stock (two peices), wiring to run the battery from the stock to the gearbox (battery end has Deans connectors, other end is bare), short wiring chunk with more deans (I use for charging battery), a loose regular Tamiya connector (small female) and a couple of pieces of shrink tubing. No instructions or other hardware are included.
Intalled in less than 10 minutes, including wiring for large battery in the stock (not included). Just fold your existing stock, remove the tiny allen screw that locks hinge pin in place at the bottom (1.5mm) slide the hinge pin up & out, remove existing stock and reverse the procedure with the G&P stock. I used a very small amount of Locktite 222 on the allen screw before torquing it in to make sure it won't come out unless I want it to.
While some retailers say you can't fold the stock with a large battery installed, you really can. The issue is the wiring which now runs through the stock into the rear of the receiver. Folding isn't the problem, but you might pinch the wires re-engaging the stock if you're not careful.
I ran my battery wiring through the stock, into the back of the receiver, over the gearbox (you have to pull it out to do this), in front of the hop up and doubled back a bit. Then I connected the tamyia plug to the bare wire ends and connected the harness directly to the gearbox. I suppose you could hook it to the existing wiring harness in the handguard if you wanted the option to switch to mini batteries without ripping half the gun apart. In my haste to get this puppy together, I didn't use the shrink tubing, but I should have used some where the stock folds to protect the wiring, though I don't fold the stock in practice.
After installation and some fire testing to ensure everything was hooked up properly, I shouldered my "new" rifle to check the pull. On full extension it's way too long and I stand 6'5". I adjusted it to the next shortest postion and it's 3/8" longer than G&P's G36K/E stock, just right for me. Unfortunately though, the stock cannot be shortened any further if you have a large battery inside, no room.
I'll be gaming with this setup this Saturday, so I can report how it performs in the field (with the Star G36 carry handle w/RDS).
~Edit~ Stock performed as well as expected. A bit more wobble than G&P and TM stock due to the two peice design, but nothing that isn't tolerable. The extra pull on the stock made it more comfortable for me as well. A recommended upgrade if you want to use a large battery and/or need a longer stock.