This 4-piece piston rings kit is designed for N20B20A and N26B20A 2.0L L4 turbocharged engines with a 10:1 compression ratio.It fits vehicles including 125i, 320i, 328i, 428i, 528i, X1, X3, X4, X5, X6, and Z4 manufactured between 2009 and 2018.The kit is engineered for a cylinder bore of 84.00mm and piston pin diameter of 22mm.Ring thicknesses are 1.2mm, 1.5mm, and 2.0mm.This standard size set does not require cylinder boring during installation.The kit includes four complete sets of piston rings.Compatible with OEM reference numbers 11257640166, 1125594453, 11258606459, 11258617082, 11257618811, 87-434600-00, and WG1175839.