This OEM Philips Headlight Ballast is a direct replacement for the factory headlights on a 2005-2011 Cadillac STS. The ballast is designed to work with D1S Xenon lighting technology and is certified as OE. The package includes the ballast, controller, no ignitor, and it is compatible with part numbers SHL-B-2-B-009, 10R-020459, and 9137 001 98803. The ballast is available in the original housing color and lens color for a seamless replacement.