Material: Aluminum Design and Style: Standard 0.00 specification, not requiring cylinder expansion Cylinder Bore: 84.00mm Ring Thickness: 1st ring 1.2mm, 2nd ring 1.5mm, 3rd ring 2.0mm Compatibility: Designed for N55B30 and N55B30A 3.0L L6 (2979cc) Twinpower Turbo engines OEM Part Numbers: 11258619196, 11257610297, 11257610298, 11257589824, 11257587914 This 6-piece piston ring set is engineered for precise fitment with a standard 84.00mm bore size, eliminating the need for cylinder block modifications. This is not an part.All brand mentions are used strictly for compatibility reference.