PIAA Powersports 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. 51w of consumption = 100w 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 PIAA Super Plasma GT-X bulbs offer an unmatched combination of fashion and performance with a bluish-purple color very similar to H.I.D. and the closest yet to sunlight Applcation 9006 (HB4) 51W=100W XTRA, 5000K