PIAA bulbs are engineered with XTRA Technology for greater performance per watt than any other bulb on the road. Xtra is a term coined by PIAA to designate a high-efficiency bulb that is designed to produce greater light output than its rated power consumption (i.e. 55W = 85W of light output). Greatly enhance your ability to see and be seen. A metal bond holds the heat-resistant glass tube securely to prevent cracks and leaks. A welded focus ring and one-piece filament support assures proper positioning.. Xtreme White Series of bulbs have a cool white light output that gives the driver better color recognition on depth perception and better contrast than stock halogen lamps. Blue top coat adds a slight blue tint to lamp.