We use the double layer bellows, with a thickness of 0.15mm ~ 0.2mm. It has a larger wave height and a smaller wave distance, with a smaller difference between the peak value and the valley value, which reduces the actual stiffness of the bellows and enhances the vibration isolation efficiency. The increase of expansion and energy saving in the interior can effectively guide the steam body, protect the bellows from heat insulation, and avoid being hit by the airflow. It can prevent the bellows from overloading the displacement of the exhaust pipe system during the driving process of the car, and play a role of displacement limit, etc. The diameter of the outer net (steel wire) is 0.2mm ~ 0.25mm, which has a large axial elongation, can reduce the friction resistance of the outer net sleeve and the bellows, and eliminate the noise of the friction between the outer net sleeve and the bellows. Reduce the exhaust noise caused by the exhaust system vibration, provide effective exhaust noise attenuation performance, reduce the impact of exhaust noise on the interior noise.