This muffler whistler is used to give your exhaust that sporty whistling sound. Make your vehicle sound like a turbo vehicle with the turbo system or blow off valve. Universal fitments for all vehicles models. Made from light weight aluminum. 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.