Lumatek Dimmable Ballasts allows you to set the light output to one of four settings;
MULTI-WATTAGE
Use different wattage lamps on the same ballast.
Use either a 400 watt lamp in anydimming setting, or a 250 watt lampon one of the 250 watt settings.
SUPER LUMENS
Up to 10% lumen burst at the flick of a switch
By switching to 'Super Lumens' the Lumen output can beboosted by about 10%
DIMMABLE
Ballasts can be dimmed to 50%
Sometimes the full 400 watts of power isnot required. The Lumatek dimmable allowsfor the power to be stepped down from100% to 75% or 50%
View more info on Lumatek Digital Ballasts