The O-Ring (OEM Part No. 0663213301) is a replacement sealing component used on Epiroc / Atlas Copco Boomer 282, Boomer L2D, Boomer M2D, Boomer S1D, FlexiROC T35 and associated COP 1838HD, COP 1838ME and COP 2560 rock drills. It is installed within the rock drill front assembly and related internal sealing positions to provide reliable sealing between mating components, helping prevent hydraulic fluid or lubricant leakage and reduce the entry of dust and contaminants. The 0663213301 O-Ring is suitable for routine maintenance, overhaul and seal replacement when the original component becomes worn, hardened, cracked or damaged. Public parts documentation identifies this part as an O-Ring used in the front section and O-ring set of multiple COP rock drill assemblies.