O-rings are often the first choice for engineers because of their flexibility and performance in static and semi-dynamic applications, and nearly every sealing configuration in hydraulic cylinders requires to wear of rings. Ultimately, the application and its specifications determine if an O-ring or a guide ring should be used.

O-rings are widely used to seal all kinds of the hydraulic part to keep them operating and safe. They do so by keeping necessary fluids in hydraulic systems and unwanted fluids and contaminants out. O-rings are inexpensive to make, can be used in a wide variety of applications, and are easy to use; these traits have made O-rings the most widely used seal for hydraulic applications.