UV LED Light, Ultraviolet, Gel Nail, 21 Bulbs Equipped with 21 UV-LEDs! Clearly confirms UV reaction on the irradiated object with UV light! Handy type, convenient for carrying. ※Never look directly at the light source. When using, it is recommended to wear protective glasses that cut UV rays. Power supply: 3 AAA batteries (sold separately, manganese batteries and rechargeable batteries recommended) ■Customer Reviews I purchased it to use for inspecting stains, etc... I purchased it to use for inspecting stains, etc. I checked the carpet for stains, but I'm still unsure how to use it and am considering it. I knew that there was ultraviolet printing on postcards, so I checked and found a barcode on 1 out of 5 postcards. It seems it can also be used for investigating personal information. For finding mold in the bathroom and making glow-in-the-dark wallpaper glow... I purchased it to find mold in the bathroom and to make glow-in-the-dark wallpaper glow. The glow-in-the-dark wallpaper doesn't glow with LED lighting fixtures, but it glowed for a while just by shining this light on it for a few seconds. I am very satisfied with the product as expected.