Engine pistons rings set designed for N52 3.0L inline-6 engines with a compression ratio of 10.7:1.Compatible with various vehicle models equipped with the N52 engine, including those with chassis codes E90, E60, E83, E84, E70, E85, and E65.Fits engine variants commonly found in 128i, 328i, 528i, X1, X3, X5, Z4, and 730i applications.This set includes 6 pieces of piston rings.OE/OEM reference numbers: 11257558528, 11257559434, 11257536373, 11257561848, 11257547838.Installation instructions are not included.Professional installation is recommended.To confirm fitment, verify compatibility with your specific engine model or provide vehicle details for confirmation.