The O-Ring (OEM Part No. 0663613600) is a replacement sealing component designed for use in Epiroc / Atlas Copco rock drill assemblies. It is compatible with selected COP rock drill models including COP 1638, COP 1838HD, COP 1838ME, COP 1840, COP 2160, COP 2238HD and COP 2560. The 0663613600 O-Ring helps provide reliable sealing between mating components, maintain fluid and pressure retention and reduce leakage during drilling operation. It is suitable for routine maintenance and replacement when the existing O-ring becomes worn, hardened, damaged or loses sealing performance. The 0663613600 O-Ring helps maintain stable rock drill operation and protect internal components from leakage-related wear.