Double bulbs on one holder. H4/H: two buls on one holder with two functions. One xenon bulb for high beam and one halogen bulb for low beam. H4/L: two buls on one holder with two functions. One xenon bulb for low beam and one halogen bulb for high beam. 1. Super brightness: its luminous flux (3,000Lm) is 3 times as that of the halogen tungsten lamp (800Lm), so that it can emit more light, radiate to higher,wider and farther place, and make you have a safer driving. 2. Extremely long life-span: The halogen lamp can only last 400 hours continuously at most, while HID Xenon lamp's life-span is 3,000 hours, which is the same with the Automobile's life (the European standard). 3. Excellent power saving: Halogen lamp usually consumes about 55-65W electric power on average. But HID Xenon lamp only consumes 35W, which can draw less power about 50% from your vehicles electrical system and obviously improve the performance of the vehicles. Saving electricity equals to saving petrol. 4. Brilliant colour tempreture: Compared to 3,000-4,200K for halogen lamp, The colour temperature of HID Xenon lamp is approximately 5,000-8,000K, wich is comfortable to our eyes, and also benefit for safe driving. 6000k, the effect is close to the daytime that the sun is shining , and it is the right acceptance and comfertable for eyes. Such lights can effectively reduce the visual fatigue driving, and have the indirect advantage for drving safety. 6000k and 8000k would have the best lumen. 5. Working voltage: ballasts can work under the DC voltage about 7-23v, can adapt to the different models. 6. Protection functions: overpressure protection, less-pressure protection, empty-loading protection. Short-circuit protection, connect in reverse protection, waterproofing, dust control, earthquake proof performance. 7. Quick-start function: when the input current is the standard voltage of electric about 12.8v, the currents is no less than test about 8.5A. The diffuse light can reach 20% about the standard brightness, when the connected xenon lamp be start within 1 second. The diffused light can reach 80% about the stardard brightness within 4 second. 8. Reliable security: Sealed by advanced technology, HID Xenon lamp engages with the features of high intensity, waterproof, dustproof, shockproof. 9. Convenient installation: Only insert HID Xenon lamp into the original lamp hole, fix ballast and connect power supply. No need to alter any part of original vehicle. 10. Kit contents: 1) 2pcs bulbs 2) 2pcs ballasts 3) 2pcs brackets 4) 1 pc User's manual 11. For D2S D2C D2R, price without wires, if with wires, price add US$6.00/set. 12. Special colour like golden-yellow(3,000k), dark blue(30,000k), Green, purple, pink, Packing: black/yellow/blue carton box or aluminium box