The Precision BG-N8 Battery Grip for Nikon D300/300s is designed specifically for the Nikon D300 and 300s DSLR cameras and accepts one EN-EL3e, EN-EL4 or EN-EL4a battery in addition to the battery in the camera body. With two batteries installed, your shooting time is effectively doubled. More so, when one battery is drained, it can be removed and recharged while you continue shooting with the other battery. Utilizing the included battery holder, it can also function with 8 AA batteries installed. 

The design of a battery grip offers a comfortable and secure way in which to hold your DSLR, especially in the vertical position. And the BG-N8 comes with an alternate shutter release button, AF-ON button, multi-selector and main and sub-command dials to facilitate shooting when the camera is held vertically. In addition, the BG-N8 is designed with anti-slip rubber grip to further improve handling, a tripod socket to mount your camera directly to a tripod and a wonderful touch: a holder for the camera's contact cover so as not to lose it when it has been removed to install the battery grip.