I ordered this K&F CONCEPT NP-W235 2400mAh Battery to use in my Fuji GFX100s.

The GFX100s is a great camera, but battery life is not so great. Instead of using a larger battery, Fuji chose to use the smaller battery from their Fuji-X cameras to keep the 100s as small as possible. While I appreciate the form factor of the 100s, I'm not a fan of how many batteries it goes through during a heavy day of shooting. And because I often carry more than one camera, that means carrying a charger for each battery type.

Kudos to K&F CONCEPT for eliminating the need for a separate battery charger. This battery has a USB-C input that allows you to charge the battery from any source of USB power. I tested the battery life and I did not really see any difference between the K&F CONCEPT and my OEM Fuji battery. I should note that the OEM battery is about a year old, so it has probably degraded somewhat whereas the K&F CONCEPT is new. As for recharge time, it took under 3 hours to go from a dead to fully charged.

I did try to recharge the K&F CONCEPT with the OEM Fuji charger and got no errors, so if you want to use a standard charger, you can. Personally, I'll be replacing all of my W-235 batteries with these as they age and lose the ability to hold a decent charge.