The Sto-fen OM-400 Omni-Bounce Flash Diffuser for Nikon SB-400 is designed to custom fit the Nikon SB-400 strobe. You don't have to use velcro to attach the diffuser and it is small enough to fit easily into your pocket or gadget bag. The Omni-Bounce creates a diffused light effect, giving even coverage across your subjects. It can be used with lenses as wide as 15mm to 200mm long. The Omni-Bounce goes on and off of your flash in seconds because it is custom fitted, so no velcro is required.