OEM Replacement HID Ballast - Direct replacement for BMW 1, 2, 3, 5, 7 Series, X1, and Z4 models (2009-2012). Compatible with OEM part numbers 63117237647, 7237647, and W003T20071. Plug & Play Installation - Easy, direct-fit replacement for your factory HID ballast. No modifications needed, ensuring a hassle-free installation process. High-Performance 35W Xenon HID Ballast - Designed for optimal performance with 35W power output, ensuring bright and reliable headlight performance. Durable & Waterproof Design - Built to withstand harsh conditions, this ballast is 100% waterproof, shockproof, and vibration-resistant for long-lasting durability. Compatible with D1S & D2S Bulbs - Works seamlessly with D1S and D2S HID bulbs, making it a versatile replacement for various BMW models.