The Battery Grip for Sony a9, a7 III and a7R III Series Cameras can be installed directly into the camera's battery chamber, just remove the door and attach it to the side of the grip's stem. Align the grip and camera contacts inside the chamber to ensure power is being supplied to the camera, and tighten the grip against the body via the thumbscrew in the 1/4"-20 tripod socket.
Once the grip is installed, the grip accepts two NP-FZ100 rechargeable batteries which doubles the camera's battery life and shooting time. The grip offers a comfortable, extended, rubberized, non-slip grip, and a shutter release button for vertical use. It also provides front and rear dials, C1 and C2 function buttons, AF-ON and AEL buttons, and a Multi-Selector Joystick, so you still maintain full functions of the camera while shooting vertically