This 400w lamp gives an output of 140 lumens per watt (56000 lumens) . The crystal glass used offers consistant thickness which allows a more even light output. There is raised blue levels in the spectrum output. The design of the lamp has avoided the use of barium film which means no blackening of the glass and less gas impurities in the lamp. It also allows for a cleaner more stable light output. The E40 mechanical double layer base design eliminates soldering and paste and delivers a 100% inline base.