4.5” of pure carbon power. Presenting the S-FLO Carbon Inlet Tube: for the Audi 8V RS3 and Mk3 TT RS: The S-FLO Carbon Inlet Tube is the largest amongst its peers, with impressive adaptability to facilitate maximum gains. The colossal 4.5” S-FLO Carbon Inlet tube bridges the gap between the turbo inlet pipe and the factory airbox seamlessly. The S-FLO Carbon Inlet Tube is for drivers looking to extract the most out of their factory airbox while increasing throttle response. Upgrade path: The S-FLO Carbon Intake Suite is modular by design allowing an easy evolution from the S-FLO Inlet Tube or S-FLO Shortie Carbon Intake to the full S-FLO Carbon Intake Systems (open or closed). S-FLO 4” Coupler: The S-FLO Carbon Inlet Tube come complete with a 4.5” to 3” couplers to mate to the factory 3” turbo inlet pipe. The S-FLO 4” Coupler transitions from 4.5” to 4” to accommodate aftermarket turbo inlet pipes that are 4” in diameter and is available separately (SKU: 7260-11002).