The 500 watt Novatron 4110 is used in our CL products of continuous light instruments. Our CL instruments can use either the 250 watt lamps or the 500 watt 4110 lamps. The CL units hold two separately controlled lamps. For professional video work,where these lamps are on for long periods of time,most users should buy a small box of these lamps and take them on location with them. These lamps are small enough to travel in the Novatron cases for our continuous light line.