Fluker's Basking Spotlight Incandescent Reptile Bulb is a basking bulb to be used when you need to direct heat and light towards a specific area in the cage for basking reptiles. It helps provide the radiant heat (or infrared light) that reptiles need in order to survive and thrive. Reptiles need access to the correct environmental temperature range (ETR) to regulate their core body temperatures. ETRs vary from species to species, so take care when choosing the correct bulb. Fluker's Basking Spotlight bulbs each have a 3,500-hour life under normal usage.