Description: Our 55W ballast is Aluminum housing ballast, it is much better than other plastic housing, as Aluminum has better heat dissipation than plastic housing AC ballast is higher price, much better, much safer, much brighter, more durable, much stable color, much longer life span than for DC ballast This main board of ballast is bigger than other seller's 55W ballast, so that ours has much better heat dissipation for Protection Function: Short/out put for protection in 1.5 sec by shutdown Constant Power Performance: When the input voltage at 7-18.5V, ballast output power can be kept constant at 42W (deviation of no more than plus or minus 3W) about protecting for HID bulbs from damage. Waterproof, Heatproof, Shockproof, Anti-Electronic Interference and Constant Power Output Compatibility: Car, motorcycle, electric motor car Material: Aluminum housing Voltage:55 Watt and 12Volt Start Voltage Range: 9V-16V Working Temperature: -40C-105C Life Time: >3600 hrs Size:8.5 x 6.5 x 1.5cm/3.3'' x 2.55 x 0.59'' Length:36cm/14.1'' Xenon for HID Advantages: Greater Visibility - 3 times brighter more consistent illumination of the road than factory halogen bulbs, and increases comfort & reduces fatigue when driving at night. Easy installation - Just plug and for play, NO modification is required. Durable and Waterproof - Build to work in all season Low power consumption - only consume 35W of electricity, 3 times more efficient than traditional halogen bulbs, 35% less power consumption, thus generate much less heat during operation. 6-Produces blue-white light that is safer because it is closer to natural daylight Package includes: 1 x 55w for HID xenon light