2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Audio

Since you're going to be spending a lot of time in your Sierra/Silverado's cab, you should at least enjoy premium sound quality when you want to blast your favorite tunes. The factory sound system on your 2004.5-2005 GM 6.6L Duramax LLY build doesn't offer up the best sound quality or range, so pick up some aftermarket speakers and subwoofers to give your audio system a new lease on life and blow the stock speakers out of the water. No matter what your intended applications may be, improve the sound quality on each of your adventures with any of the premium GM 2500/3500 audio upgrades we have in store. GM Duramax Fitments: 2004, 2005 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.