The critical fact for the proper operation of the engine is to keep the lubricating oil clean, or to ensure no corrosive impurity inside the lubrication oil.

　　 By using the special filter papers, the oil filter manufactured by QiRui Co.,Ltd can ensure the good filtering performance. The impurity inside the lubricating oil can been removed effectively, and the maximum filtering efficiency and minimum wearing of the engine can been reached under minimum pressure difference, the life duration of the engine can be prolonged.