Uniquely designed with a patented combination of retroreflectivity and photo luminescence, Glo-Flex. Star of Life emblems reflect bright white when light strikes and glow a brilliant fluorescent green in total darkness. Glo-Flex glows exceptionally bright at the beginning and diminishes 80% in the first 30 minutes and continues to glow at a low level an additional eight hours. Glo-Flex is visible through smoke and fog and also provides all of its safety properties when wet.