Rod seals for hydraulic cylinder: Rod seals are considered the most critical element of a cylinder sealing system. They prevent the leakage of fluid from within a hydraulic cylinder to the outside as the rod cycles back and forth (dynamic pressure sealing). Rod seals work together with wiper seals to protect a hydraulic system against external contaminants such as dirt and outside weather conditions.

The common type of rod seal is lip shape seal (it is generally called a Y shape seal or U shape seal). Rod seal is required good pressure holding performance in a static state, while good sealing performance, small friction factor, and strong anti-extrusion ability in a dynamic state. 

Common rod seals are IDI, ISI, IUH, SPNO, SPN, SPNC, UPI, USI, UPH, USH, HBY type, and so on.