6Pcs Pistons and Rings Set STD 22mm with 84.5mm cylinder bore and 54mm wrist pin length, designed for N55B30 and N55B30A engines.This set includes 6 pieces of pistons and rings with ring thickness of 1.2mm for the first ring, 1.5mm for the second ring, and 2.0mm for the third ring.Made from grade aluminum, the construction supports under performance conditions.Compatible with models including F10, F20, F30, F80, M135i, M235i, X3, X5, and X6.Engineered as a direct replacement part with OE number 11258619196, proper fitment and straightforward installation.Suitable for use in engine rebuilds or performance where internal components are required.