A blacklight (or often black light), also referred to as a UV-A light, Wood's lamp, or ultraviolet light, is a lamp that emits long-wave (UV-A) ultraviolet light and very little visible light.

One type of lamp has a violet filter material, either on the bulb or in a separate glass filter in the lamp housing, which blocks most visible light and allows through UV, so the lamp has a dim violet glow when operating. Blacklight lamps which have this filter have a lighting industry designation that includes the letters "BLB".This stands for "blacklight blue".

Fluorescent Tube (UV-A BLB Counterfeit), more commonly known as black light, or UVA black light blue light (or blacklight blue), is a special version of UVA light source enhanced to protect users’ eyes. UVA black light blue lamp uses black glass (ZWB3 | UG11) in making the glass body, which could effectively filter away undesired UV spectrum which could be harmful to eye for prolonged exposure. It is the key reason why UVA BLB light source is used in most counterfeiting machine or used in forensics due to high friendliness to users’ eyes. Same as normal UVA, it is a mercury discharge lamp which emits ultra violet light source or wavelength 365nm. Ultra violet is emitted and control by the black glass used to make the lamp body to create the desired UV spectrum. UVA light source have a very big scope application. They are used in forensics and counterfeiting machines. UVA lamp is available in different lamp shape, which can be T5, T8, PL-S and PL-L lamps. They work with most electronic ballast in the market and some small wattages can work with magnetic ballast. Solid state mercury (amalgam) could be used to improve safety, stability and environmentally friendliness of the product.

Ultra violet lamp is light on base on low-pressure mercury vapor discharge mechanism, which it is mandatory to work with an external device, which can be either magnetic ballast or electronic ballast. When power is connected, high temperature is created at the inner filament at both end of the tube. The high temperature vaporize mercury inside the tube to form a complete circuit inside the tube, which ionized mercury will emit ultra violet when hitting on the UV powder coated on the glass tube.