The Green and Gold Omni Units are used for special lighting situations.1 . The Green for Fluorescent Lighting in conjunction with an FLD or 30M filter on the Camera Lens.2. The Gold for Warming Skin tones and for overall warming in flash filled available light shots.3. They are mounted the same as the regular Omni for your Flash Unit. Fits the Following flashes: Nikon SB-50DX, SB-800, SB-80DX, Sony HVL-F1000, FH1100, Vivitar 728AF and other similar size flashes.