The function of A1 type dustproof ring is to prevent dust, dirt, sand and metal chips from entering, through special design, prevent scratching, protect guide parts, prolong the working life of seals. The diameter of interference ensures that the upper seal is tightly packed into the groove, thus preventing the invasion of impurities and moisture. A1 type dustproof ring provides a closed chamber for the cylinder, without screws and brackets, without strict tolerances, and without metal plug-ins, preventing corrosion like metal skeleton dustproof ring may occur. Grooves also do not require strict tolerances.