O Rings are circular sealing devices commonly used in mechanical systems to prevent the leakage of fluids or gases. They are made from elastic materials such as rubber, silicone, or nitrile, which allow them to fit snugly into a groove and compress between two surfaces to create a seal. O-rings are used in a variety of applications, including hydraulic and pneumatic systems, automotive components, and plumbing systems. They are prized for their simplicity, cost-effectiveness, and ability to seal effectively under a range of pressure and temperature conditions.