An ultraviolet (UV) flashlight, also known as a UV Flashlight Black Light, is a handheld device that emits ultraviolet light. UV light falls outside the visible spectrum for humans, but certain materials and substances can fluoresce or react to UV light, making it useful in various applications. It's important to note that UV light can be harmful to the eyes and skin with prolonged exposure. It is recommended to avoid direct eye contact and to use protective eyewear if you are working with a UV flashlight for an extended period. When purchasing a UV flashlight, look for one specifically designed for the purpose you intend to use it for and ensure it provides the appropriate wavelength of UV light for your needs, usually in the UV-A range.