The O-Ring (OEM Part No. 0663210053) is a replacement sealing component used on Epiroc / Atlas Copco Boomer S2, SB 152 and SBU 160 equipment. It is installed within hydraulic and mechanical assemblies to provide reliable sealing between mating components, helping prevent hydraulic fluid leakage and reduce the entry of dust and other contaminants. The O-ring supports stable operation of associated internal components under demanding drilling and mining conditions. The 0663210053 O-Ring is suitable for routine maintenance, overhaul and seal replacement when the original component becomes worn, hardened, cracked or damaged. Epiroc technical documentation identifies 0663210053 as an O-ring used in relevant seal assemblies.