DOP11351HU351 Husqvarna 351 Cylinder Assembly with a 44mm bore. Part No. 537-25-31-02. Fits Husqvarna models 350, 351, 353. This works as a big bore for 346xp too. This kit includes the cylinder, piston, ring, wrist pin and cir clips. Replaces OEM part number 503-86-99-03, 503 86 99-03, and 503869903.