This 6-piece engine piston rings set is designed for standard bore size of 84.00mm and fits N55B30 and N55B30A 3.0L L6 2979cc twin-turbo engines.Cylinder bore: 84.00mm.Wrist pin diameter: Φ22mm.Wrist pin length: 54mm.Ring thickness: 1st ring 1.2mm, 2nd ring 1.5mm, 3rd ring 2.0mm.Compatible with a wide range of models including 135i (E82, E88), M135i, M135i xDrive, F20, F21, M235i, M235i xDrive, F22, F23, F87, 335i (E90, E91, E92, E93), 335i xDrive, F30, F31, F80, ActiveHybrid 3 Series, Gran Turismo 335i (F34), 435i, 435i xDrive (F32, F33, F36, F82, F83), 535i (F10, F11), 535i Gran Turismo (F07), 640i (F12, F13), X3 xDrive35i (F25), X4 xDrive35i (F26), X5 xDrive35i (F15, F85), and X6 xDrive35i (E71, E72, F16, F86).