Description: 348-8779 is an intermediate piston ring. Cat intermediate piston rings are split rings that fit into a groove on the OD of the piston body between the top ring and the oil ring. Piston rings function to form a seal between the piston body and the cylinder wall that prevents the loss of combustion cylinder gases to the crank case, maintains a constant level of lubricating oil between the cylinder wall and the piston and regulates engine oil consumption by scraping oil from the cylinder wall back to the sump.