The Green Extreme Professional Power Battery Grip for the Nikon D850 is an optional but essential accessory with excellent ergonomics designed specifically for the Nikon D850. Featuring intelligent links to camera functions, matching the design and feel of your 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 taking advantage of the camera's movie mode or Live View mode - operating modes that use more power compared to using a single EN-EL15a pack. In addition, with the included battery magazine, you can also run the camera off eight AA batteries just make sure to select the correct AA battery type in the D850's setup menu. the grip can also be used with an EN-EL18b battery when paired with the BL-5 cover or power the camera directly via AC with an EP-5B power supply connector and EH-5c adapter combination 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 vertical 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 the grip has a standard 1/4-20 tripod socket and a hand strap mount. Your ca