The dummy battery takes the place of the Sony NP FZ100 battery pack. it is the best choice for a long time photography for studio and indoor shooting. the power adapter continuously provides unlimited power to the camera through the ac outlet, no needs to replace the multiple batteries and the power supply charger, for you to complete long-term studio shooting, shooting video recording. Compatible with Sony Alpha a9, a7R III, and a7 III Mirrorless Digital Cameras