Opteka is one of the world"s leading producers of high-performance batteries and accessories. Opteka believes there is no limit to the potential of portable power and as a company they will always strive to find innovative and efficient ways to power your life in the future! The Opteka FBH-N30 holds 2 EN-EL3 / EN-EL3e batteries. This provides an extremely extended shooting time. Vertical shutter release also makes shooting with the camera in a vertical position just as comfortable as shooting horizontally. Compatible with Nikon D300 & D700 SLR Camera only.