Folomov A1 Portable Magnetic USB cable charger with charging and discharging function, for Li-ion battery 26650 21700 20700 18650 16340 14500 and More

You can get it to charge, and the light flashes to indicate charging, but if you run it through a usb multimeter it shows that unless you push the positive lead slightly to the side you don't get a solid connection and the charge rate is literally 10x slower (same for discharging.)I'm sure that they could probably make a full connection with some, but I tested two different brands and both had same issue.As a side note, I've no idea how they'd handle flat tops you find in vapes either.

Keep this in your bag or EDC pouch. Awesome little bit of kit. Not only does it charge your cells, but you can also use any cell you have (li-ion only) to charge a portable device.

Works like a charm