This wiring harness is designed for use with 2004 and 2005 GMC 6.6L Duramax Diesel engines and manual shift transfer cases. It is made specifically for GM vehicles and is a high-quality wire harness that will ensure the proper function of your vehicle's wiring and electrical systems. The harness is easy to install and will provide you with reliable performance for years to come. It is a great addition to your vehicle if you need to replace or upgrade the wiring system.