This set includes 4 piston rings with an 84mm bore diameter and 22mm pin diameter, designed for use with N20B20A, N20B20B, N20B20D, and N26B20A engines.These components are compatible with select models including the 125i, 220i, 228i, 320i, 328i, 428i, 528i, X1, X3, and X4.Made from cast iron with a nural-type coating, the rings offer and resistance to wear under normal and performance driving conditions.The design supports proper engine compression and helps reduce oil consumption in turbocharged four-cylinder applications.Each set includes four piston rings for a complete replacement solution during engine rebuilds.