I bought this plus the Sony NP-FW50 adapter. The price is a bit high, but it's the price.I am pairing this with a RAVPower 16,750 mAh battery. It has worked flawlessly. I have installed the adapter into the Neewer battery grip for the A7 series. I had to make a modification to the grip and battery chamber to cut a hole for the cable.I have used this to shoot about 1,500 photos in an afternoon. I loved that I never had to worry about loss of battery power, which is a valid concern with the Sony A7 camera (all digital cameras, to be fair).If I were to do it over again, I would get that little thing that connects the system power cable to the power cable that goes to the dummy battery. I lost power a few times when I accidentally disconnected the power cables.This aside, I've shot with this accessory a number of times and am very pleased with it.