Compression rings are essential components in an engine's piston assembly. They are designed to create a tight seal between the piston and the cylinder wall, preventing the escape of combustion gases and maintaining optimal pressure within the combustion chamber. This sealing action helps improve engine efficiency and performance. Typically made from durable materials like cast iron or steel, compression rings are shaped to fit snugly in the piston grooves. Over time, they can wear out due to heat and friction, which may lead to reduced engine power and increased oil consumption. Regular maintenance can help ensure their longevity and effectiveness.