Suitable for ModelThis whistle is suitable for Honda Accord Acura. For specific suitable models, you can view the following parameter information [Must be a turbocharged engine] This whistle can only be used on a turbo engine, a naturally aspirated engine, even if it is installed, there will be no whistle sound. SizeThe size of this whistle is: Length: 11cm * Width: 3cm. Make sure this whistle is the right size for your exhaust. Exhaust pipes of different diameters need to be installed with the appropriate size. Only then does it maximize the return ofthe exhaust to the turbo, increasing the speed of the airflow and making a whistle-like sound in the turbo. [Function] The whistle sound is emitted through the airflow of the exhaust pipe.