Blue Silicone Air Intake Boot (MMHOSE-E46-01IBL) by Mishimoto. Includes: Silicone Hose. Inner Diameter: 3.87in & 5.75in x 4.49in. Outer Diameter: 3.27in & 5.15in x 4.89in. The Mishimoto Silicone Intake Boot is made from a combination of high-grade silicone and heat-resistant embedded fibers for a high-quality replacement kit for your OEM rubber hoses. Mishimoto silicone hoses retain OEM fitment while providing increased pressure tolerance for the ultimate upgrade in performance and style.