6pcs Pistons Rings Set STD 84mm for F20 F21 F30 F10 X3 X4 X5 X6 E82 E88 N55B30 N55B30A 3.0L L6 2979cc Twinturbo 11258619196 Material: Aluminum Design and Style: Standard 0.00 spec, not requiring cylinder expansion Cylinder Bore: 84.00mm Ring Thickness: 1st ring 1.2mm, 2nd ring 1.5mm, 3rd ring 2.0mm Compatibility: N55B30 and N55B30A 3.0L L6 (2979cc) Twin turbo engines OEM Numbers: 11258619196, 11257610297, 11257610298, 11257589824, 11257587914 This 6-piece piston ring set is designed for use with specific inline-6 twin turbo engines.Constructed from aluminum, the components are engineered for under function conditions.The standard 84.00mm bore size allows direct installation without cylinder modification.The set includes three rings per cylinder with progressive thickness to support effective sealing and reduced oil consumption.The 1.2mm first ring, 1.5mm second ring, and 2.0mm third ring are dimensionally matched to proper function within the designated engine platform.Designed for precise fitment, this piston ring set supports engine efficiency and consistent.It meets OEM specifications for dimensional accuracy and thermal resistance, including function at operating temperatures up to 105°C.The design supports compliance with emission standards when installed in the correct applications.