Satco's 40-watt, T12 fluorescent blacklight features a medium bi-pin base and up to a 20,000 hour life span. Blacklight linear bulbs emit ultraviolet (UV-A) light which can be used for numerous applications. Whether they are used in hospitals to check for the cleanliness of surfaces or in a bug zapper to create a pest free environment, these lamps are sure to meet all of your lighting needs.|Satco's S6409 40-watt, T12 fluorescent blacklight features a medium bi-pin base and up to a 20,000 hour life span. Blacklight linear bulbs emit ultraviolet (UV-A) light which can be used for numerous applications. Whether they are used in hospitals to check for the cleanliness of surfaces or in a bug zapper to create a pest free environment, these lamps are sure to meet all of your lighting needs.