This piston ring set is designed as a direct replacement for worn or damaged components in engine rebuild, repair, or maintenance applications.It is engineered to provide accurate fit and function for specified engine models.Specifications: - Part numbers: 11257649927, 11258073574, 11258485797, 11257844774 - STD 0.00 specification; no cylinder overbore required - Cylinder bore diameter: 89.00mm - Ring thickness: 1st ring 1.2mm, 2nd ring 1.5mm, 3rd ring 2.0mm - Engine compatibility: N63B44 4.4L V8 (4395cc) Twin Turbo, S63B44 4.4L V8 (4395cc) Twin Turbo - Engine models: N63B44C, N63B44D Compatible vehicle applications: - 550i Gran Turismo (2013–2017) - 550i (2013–2017) - M550i xDrive (2016–2020) - M5 (2010–2019) - 650i (2013–2018) - M6 (2011–2018) - 750i / 750Li (2013–2019) - M850i xDrive (2017–2020) - X5 50i xDrive (2014–2020) - X5 M (2013–2018) - X6 50i xDrive (2014–2020) - X6 M (2014–2019) - X7 50i xDrive (2018–2020)