The Green Extreme Professional Power Battery Grip for the Sony Alpha a9, a7 III & a7R III is an optional but essential accessory with excellent ergonomics designed specifically for the Sony Alpha a9, a7 III & a7R III Cameras. Featuring intelligent links to camera functions, matching the design and feel ofyour camera while doubling the battery power with a twin cell chamber that can load a choice of one or two battery packs. This is especially useful when takingadvantage of the camera's Movie Mode or Live View mode - operating modes that use more power compared to using a single NP-FZ100 Pack. The non-slip rubberized grip offers perfect balance in any direction with full vertical shooting controls, which can be independently turned on or off as the photographer needs to enhance camera handling, especially for shooting vertical pictures - not videos, please. The grip has generous operating controls as well:shutter button, Main Dial, multi-controller, AF point selection button, AE lock/FE lock button, AF start button, and multi-function button. The base of thegrip has a standard 1/4-20 tripod socket and a hand strap mount. Your camera's original battery door fits snugly in a protective hidden slot for instant retrieval. Get a grip. The VG-C3EM 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 b