Great cord for hooking up your GPS unit and Nikon compatible camera. This allows you to record the longitude, latitude, elevation, and heading. The only downside is making sure that the GPS unit is pointed in the same direction as the camera and the GPS is not in "sleep" mode. My camera, the D300, will let you know if the GPS is not active. As a professional, it's nice to be able to locate those special locations by just looking at the image data and also knowing what direction you were shooting.