Hella Optilux XB xenon blue light bulbs, H4 12V 100/80 Watt. These bulbs are filled with xenon gas and utilize a blue quartz glass which allows the bulbs to simulate the color of actual daylight. Great assist when driving in rain or dark winter nights. Bulbs are sold in a set of two. Due to the high light output these bulbs are only for off-road use!