Find the Intake Couplers & Elbows you need to complete or repair the cold air intake system on your 2004.5-2005 Chevy/GMC 6.6L LLY Duramax. These couplers are constructed from plastic, rubber, or silicone, and come in 3.5" up to 6" diameter. Find a large selection of 90-degree, hump, straight, and reducing couplings. AFE, Fleece Performance, Vibrant, and Grand Rock are just some of the high-quality companies available at XDP.