ZITAY USB to NP-FZ100 Dummy Battery with Charging Indicator for Sony Alpha A7 III A7R III A7R IV A9 II A9R A9S A7R3 A7S3 FX3 Cameras

I tried this as soon as it arrived. I wanted to be able to set up my Sony A7iv and record video at any time, without having to charge batteries (and at the moment I only have the one battery for it).This works perfectly, although you do have to take into account their instructions. You can't use a 5v power source, so whether you use an adaptor or a powerbank make sure it's giving out 9v or more (QC power works I believe).So why 4 stars? Well the cable from this dummy battery prevents me from closing the battery door - at least I haven't found any way to do it without trapping the cable itself. I'd have preferred it if they had some kind of flat ribbon type cable, but I realise that may not technically be feasible.That aside, it works and it means I can plug in and record any time I want. The fact it will run off a (suitable) powerbank is a big plus too, since I didn't really want mains cables all over the place.If you need to power any camera that uses the FZ100 battery, this will do the trick. Just be aware of those two points I've made and decide whether they are an issue for you personally.