DOP11312 Partner Husqvarna K1250 Active Cylinder Assembly No. 506-29-42-71. This is a quality aftermarket Nikasil Plated Cylinder that Includes cylinder, piston, rings, pin, and e-clips. Replaces Partner / Husqvarna No. 506-29-42-71, 506 29 42-71, 506-29-42-71, and 506 29 42-72.