The Nikon SU-800 allows you to wirelessly trigger any number of flashes from your camera. The benefit of the SU-800 is that it uses an infrared beam instead of a flash of light. It can control up to three groups of flashes with any number of speed lights in each group. This is the perfect tool for off camera flash. I have two and I'm selling my second unit. Comes with soft case and is in great condition.