Rogue Gels are cut from LEE Filters optical lighting material. LEE Filters are superior to other brands because they coat both sides of a thicker base material to ensure more uniform and accurate colors. Color correction gels are used to improve color balance in an image by adjusting the color temperature of the flash to match ambient light sources. How to use. Identify your light source and attach the corresponding color correction gel(s) to your flash. Set a custom white balance, or set the camera to the same white balance setting printed on the attached gel. CTO gels are used to color balance flash to incandescent, tungsten, or halogen light sources. Plus Green gels are used with CTO gels to color balance flash to fluorescent light sources. CTB gels are used to color balance flash to blue sky. Rogue Flash Gels attach quickly to most flashes from Canon, Nikon, Nissin, Lumopro, Olympus, Panasonic, Sony, Yongnuo. They can be trimmed to fit smaller flashes as desired. Contents: 3 Rogue Gel bands, 1 storage pouch, 1 reference chart, 3 each LEE color: 1/4 CTO, 1/2 CTO, Full CTO, 1/2 CTB, Plus Green, Full White Diffusion (1 f/Stop).