S size is suitable for the displacement of 1.0-1.6, the diameter of the exhaust pipe is 32-43 mmM size is suitable for 1.6-2.0 displacement, exhaust pipe diameter is 37-48 mmL size is suitable for 2.0-2.4 displacement, exhaust pipe diameter is 44-55 mmProduct introductionProduct name: car exhaust pipe whistle car whistle, throat, drum, modified imitation turbo pressure relief soundProduct color: silver gold black blue purpleProduct Features: This product has the same sound as a whistle, suitable for any car model, easy to install, beautiful and elegant, very fashionable and low cost, it is the first choice for decorating your car.Note that it's not the sound of a sports car It's the sound of a flute.Note: The product is only suitable for straight exhaust pipes, curved exhaust pipes cannot be installed