Ace Race Parts 27315 Transition Turbo Flange - Undivided T4 to Single 4.000 OD Tube - 304 StainlessAce Race Parts 27315 Transition Turbo Flange Undivided T4 to Single 4. 000" OD Tube 304 Stainless 304 STAINLESS BILLET TRANSITION TURBO FLANGE UNDIVIDED T4 TO SINGLE 4. 000" ID The Ace Race Parts brand of Transition Turbo Flanges is designed and precision CNC machined to offer the smoothest possible transition from a T4 open housing to 4. 000" outside diameter tube size material. Each flange is precision machined from solid 304 Stainless billet and is