Our high quality silicone hoses are at least .4" bigger in inner diameter over stock hoses. Custom Cnc machined aluminum adapters with 2.2" inner diameter vs stock allow more volume of air due to less restriction at the connection. These hoses are hassle free direct fit and perfect with our custom 3.5" direct replacement intercoolers. F hose included. For those opting to even bigger opening at the intercooler/hose connection, we offer these hoses with our custom 3.5" intercoolers using 2.25" hose to intercooler connection for even more flow.