This video tutorial is going to show you how to use the Nikon SU-800 Commander speed light. It requires only one 123A 3V Lithium Battery. A tiny switch allows you to switch between close-up. Another flash can be connected to it by a long cord. SEL button allows you to select. With the left and right arrow buttons increase or decrease the flash power. You will use the MODE button to program the speed light. TTL is for through the lens, AA for auto aperture, M for manual and so on. Watch the full video tutorial for other details about the Commander speed light.