Philips NightGuide is the most advanced halogen bulb we've ever developed, providing a level of safety, style, and performance unmatched by any other halogen on the market. NightGuide headlamp bulbs feature special technology that projects specific colors of light into three distinct visual zones, to dramatically improve nighttime visibility. In the center zone, a brilliant white beam, up to 50 feet longer than a standard halogens, improves driver's vision and reaction time. In the right zone, blue light enhances readability of road signs and markers. In the left zone, yellow light reduces glare for oncoming cars and improves driver's concentration on the center zone.