3.50 to 4.00 Inch Hump Transition / Reducer Coupler Silicone Turbo Hose Quality: Premium Grade Silicone Turbo Hose, reinforced with multiply Ply high-heat resistant Nomex (no polyester used) Performance: HoseTechniques hoses are used in many high performance race cars by world famous drivers s Style: HoseTechniques hoses will transform your cars engine from mild to wild. Other products and colors to compliment your purchase are also available from our main website. HoseTechniques.com - The Best Silicone Hose on the Block! 3.50 to 4.00" ID - 3.50" Long - 3 Ply Nomex - 0.170" Wall - Silicone