This 4-piece piston rings set is designed for standard bore applications in 2.0L TDI diesel engines with CRB, CZH, or DFG configurations.The set is compatible with select A4 B9, Q3, and Q5 models.Each ring is manufactured to meet standard dimensional and functional specifications for proper fit, compression sealing, and oil control.This product replaces 04L198151C.Installation requires standard mechanical tools and familiarity with engine assembly procedures.