U-V-Killer blocks ultraviolet reflection and luminescence. For all fabric, camouflage, and blaze orange. One bottle will treat two sets of hunting clothes.  The original U-V-Killer has changed how hunters think about camouflage. It has been proven that animals and birds have sensitivity to ultraviolet light and the 438nm short-blue wavelengths that humans are blind to. U-V-Killer absorbs U-V wavelengths and thereby eliminates the blue glow caused by fabric dyes and detergents that contain U-V brighteners.