New Fashion Fluorescence Baseball Cap Women Men Snapback Caps Luminous Gorras Sport Casquette Hip Hop Cap HatIs the hat always shining? To be exposed to natural bright light, incandescent lamps bright light, ultraviolet light and other irradiation, the light energy stored, in the stop exposure, slowly released in a fluorescent way, so in the night or in the dark can see the glow for a period of time. How long can you shine? Absorb strong light for 5 15 minutes and emit light for about 30 60 minutes. What is the luminous material? Luminescent materials are