The Calumet 4-Flash speed ring adapter is compatible with the Calumet RM6400 speed ring & Calumet RD3100 to allow four shoe-mounted flash guns to powerfully illuminate your softbox or umbrella. You can also use the directional heads of the flashguns without a softbox to control the light to create a range of creative effects. Using the wireless capabilities of Canon & Nikon’s wireless flash technology you have the added benefit of no cables as well as being ultra-light & portable.