Delivering consistent fuel from your tank to the injectors is important to ensure maximum diesel performance and reliability. Our selection of Injector lines ensure that your trucks fuel is transported efficiently and consistently at the right pressure to each injector, which then delivers the fuel into the combustion chamber. GM Duramax Fitments: 2001, 2002, 2003, 2004 GM 6.6L Duramax.Submodel Fitments: WT, Custom, LT, LTZ, High Country, 1LT, 2LT, Pro, SLE, SLT, AT4, Denali.Some exceptions apply, please see individual product pages for specific fitments.