The Ten-pin remote and flash sync terminals on the Nikon D3/D3x have rubber caps that are attached to the camera. This is a big improvement over the small screw caps that were on previous models. However, I found that the rubber caps would sometimes get in the way when attaching remote cords. The other day, I was attaching a remote, and had a moment of clarity. The rubber caps actually rotate, so you can move them out of the way. This is shown in the photo. It’s only taken me a 18 months of using the camera to find this neat feature!