Update: On my new A7V, the battery warning does appear.

Original:K&F Concept has earned a reputation for making high-quality, affordably priced camera accessories. This charger and battery package is another example.

Let's start with the charger. The USB-C charger is fairly simple, but effective. It doesn't include a power adapter, but I have so many already that I'm relieved not to have bought yet another one. It can charge two batteries simultaneously. Each battery has a bright and easy-to-read charge level indicator.

The batteries seem fine in terms of capacity. What distinguishes these from many other non-Sony batteries is that they don't trigger that annoying warning from the camera which can be pretty frustrating when it interrupts you at the most inconvenient moment.

The manufacturer states that the charger and batteries have a wide array of protective features including "Overcharge / Overheat / Overcurrent / Overvoltage / Short-circuit protection". Don't overlook the importance of these. I wish I had a way to test these features, but since I do not, at least I feel that I can trust K&F Concept's claims.