H11b XTreme White Plus Twin Pack Halogen Bulbs Headlight Bulb Replacement Guide The H11b Xtreme White Plus Series of high output replacement bulbs give drivers better color recognition, depth perception, and improved contrast over stock halogen bulbs, all while meeting DOT specification. Xtreme White Plus bulbs feature a crisp white light output that allows for better road illumination, while a blue top coat adds style toyour vehicle with the Xtreme White's 4000k color temperature. ...