Description SZ XL Universal Turbo Sound Exhaust Muffler Pipe Whistle Blow-off BOV Simulator.Make your vehicle sound like a turbo vehicle with the turbo system or blow off valve. Specification: Size:XL 35mm(Diameter),Tail Pipe:56-85,Lenght:12,Displacement:2400+ cc. Installation: Loosen the screw on the Turbo Sound Whistle. Place the Turbo Sound Whistle body inside the exhaust muffler with the larger opening facing the inside of the muffler. Screw the screws on the Turbo Sound Whistle to tighten the item so it doesn"t fall off while driving. Professional installation is always recommended, products damaged through self-installation will not be refunded.