URU rod seal ring is the main rod seal ring made of polyurethane rubber. This is a form of design that has been tested for a long time. Because of its good mechanical properties, it is widely used in the use of standard cylinders. It is especially suitable for the field of construction machinery in harsh environment. The asymmetrical lip design ensures optimal resistance to dynamic pressure in reciprocating motion. At low speeds, crawling may occur because of insufficient oil film formation. The notch on the back of the lip eliminates pressure accumulation between the sealing rings.