1. A new type of environmental filter paper is adopted to improve the efficiency of the filter element. 2. The filtration efficiency is up to 99.5%(98% of the oil bath type air filter), and the penetration rate of dust is only 0.1% to 0.3%. 3. Compact structure, can be installed in any direction, and is not restricted by the layout of vehicle parts. 4. It can also save a lot of material such as cotton yarn, felt and metal materials. 5. Low quality and low cost. Therefore, the driver can be assured to use. 6. Purify air, reduce noise and save fuel.