By far the most difficult header components to home fabricate, Hooker offers high quality stainless steel collectors. Formed on state-of-the-art collector forming machinery and offered in two sizes (1-3/4" primary tubing x 3" collector and 1-7/8" primary tubing x 3" collector), the two kits come in two styles. The Base kit comes with the formed collector and a single band clamp for easy hook up