This sealing ring is installed in the hydraulic system of the host machine to prevent fluid leakage at a joint or port. It sits between two mating faces, compressing under assembly load to block the passage of oil or hydraulic fluid. A degraded or hardened ring allows seepage, which reduces system pressure and can lead to a visible drip or loss of volumetric efficiency. The manufacturer specifies the ring's cross-section and inner diameter to match the original groove geometry, ensuring proper compression without over-stressing the seal. On reinstallation, inspect the groove for debris or damage before fitting the new ring.