The NP-FZ100 battery is used in the Sony A9 and A7-RIII. I had previously designed a battery for the A7-RII's batteries - something that was really needed given the rate you go through them. Now with the additional A7-RIII body (and battery grip), there is the need for a like holder. This holder has capacity for 2 batteries - you are unlikely to need more in one place.
There are two variants, one with batteries as for the previous holder, one symmetric