This Black Diffuser for 41" Deep Umbrella's from Elinchrom offers a way to maximize the utility of your umbrella. Actually a sort of cap, the diffuser slips over the open side of the Deep Translucent Umbrella, with your flash head in the center of it. The black exterior contains spill light while the reflective silver interior creates a wide spread of light that's soft, with a crisp edge. With the convex side (arc) of the umbrella pointed at your subject, the diffuser allows using it much as you would use a softbox.