Nikon MB-D10 vertical grip
The Nikon MB-D10 Multi-Power Battery Pack allows the Nikon D300 & D700 to powered by two EN-EL3e batteries simultaneously (one in the camera body and one in the MB-D10) effectively doubling its shooting capacity. The MB-D10 also provides a comfortable vertical grip with an additional shutter release and scroll wheel for easy access to the camera functions when shooting in the vertical orientation.
With the optional MS-D10 battery users can power the camera with 8 AA batteries or use a Nikon EN-EL4 or EN-EL4A battery (sold separately) with optional BL-3 Battery Chamber Cover to obtain higher frame advance rates (8 Frames per second in the D300) than the EN-EL3e battery can provide.