It is a turbo pressure whistle, an aluminum whistle on the exhaust pipe, and air through the exhaust pipe to make it sound. Brand new and high quality. Made of aluminum alloy, lightweight and durable. Universal fit for all vehicle models. Easy to install, it can be installed in less than 2 minutes. Periodically (after 500-1000 km) check and retighten the bolt and rock nut. Once this product is installed, the exhaust pressure will make your vehicle sound like a turbocharged vehicle with a turbo system or blow down valve. Color : gold Material: aluminum alloy Applies to: general purpose Model : L Size: (whistle caliber): L number 27mm Installation: First loosen the screw on the Turbo Sound whistle. Then place the body of the Turbo Sound whistle into the muffler with the larger hole facing the inside of the muffler. Finally, tighten the screws on the Turbo Sound whistle to tighten the piece so it doesn't fall off while driving. (Professional installation is always recommended) The package includes: 1 x Turbo sound simulator whistle 1 x Small Wrench 1 x screw