The Digital Photography Blog: all you need to know about digital cameras and photography
Here's an excerpt:
'The WT-1 attaches to the bottom of the D2H via the tripod mount and connects to the camera in two places. Firstly it takes power from the camera's battery via a four prong connector on the top of the WT-1, secondly it connects to the camera's USB port via a fly lead, the connector has a rubber seal to maintain the D2H's weatherproof status but also leaves the existing USB door hanging loose. Included with the WT-1 is a special battery door which has a wire holder molded into its side. While workable I found the fly lead setup to be a little strange, it would have been neater to add USB to the connector on the top of the WT-1.'