Find the Intake Couplers & Elbows you need to complete or repair the cold air intake system on your 2017-2019 Chevy/GMC 6.6L L5P Duramax. You will find a vast selection of hump, straight, reducing, and 90-degree couplers. These couplers come in various sizes ranging from 3.5" all the way up to 6" diameter and are manufactured out of rubber, silicone, or plastic. AFE, Fleece Performance, Vibrant, and Grand Rock are just some of the high-quality companies available at XDP.