It is the improved versions of SF-2 which makes the steel back as matrix, sinters porous bronze powder in the middle and rolls the polymer materials of acetal resins, oily fibre and special lubricants on the surface. The same production in foreign country is DS bearing, which has characteristics of low fraction, best fraction resistance and lubrication on the condition without oil to be used in the temperature situation of dry lubrication of friction and low oil. Nowadays, the product has been used to rolling movement and machinery parts easy to wear and easy to corrosion, such as volume ,printing and dyeing machine, mining machines, cranes, bulldozers and road aerial machines.