This Battery Grip allows the Nikon D300s, D300 & D700 to be powered by two EN-EL3e batteries (sequentially) - one in the camera body and one in the battery grip - effectively doubling your shooting capacity. It 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. It is also fairly compact, with dimensions of 5.9 x 2.9 x 1.7" (15 x 75 x 45mm).
With the included AA battery holder, users can power the camera with 8 AA batteries. Or, use the Nikon or EN-EL3e battery.