Features: Aluminum alloy material, solid installation, loud sound. The bigger of the size, the louder of the sound. Make your vehicle sound like a turbo vehicle with the turbo system or blow off valve. Applicable to all kinds of cars, motorcycles and racing cars. Easy to install on the car's tailpipe. Sound principle: s pressure relief whistle, aluminum whistle clamped on the exhaust pipe, makes it sound through the air flow of the exhaust pipe. Installation: 1. Loosen the bolt on the Turbo Sound Whistle. 2. Insert the the Turbo Sound Whistle into the tailpipe. 3. Tighten the bolt so as not to fall off while driving. Note: 1. Please make sure the tailpipe is big and long enough to contain the Turbo Sound Whistle. 2. Professional installation is always recommended, products damaged through self-installation will not be refunded. 3. Please check and re-tighten the bolt regularly. Specifications: Color: Silver/Blue/Black/Red optional Size: S, M, L, XL (Optional) Material: Aluminum Package List: 1 * Turbo Sound Whistle 1 * Small Spanner 1 * Screw