Piston assembly from Stihl. Complete piston assembly for your chainsaw. Piston assembly includes a piston, rings, piston pin and circlips. We recommend replacing your cylinder gaskets and using a piston ring clamp set to help when changing a piston. This piston assembly fits all 026 chainsaws and older MS 260 chainsaws. Newer MS 260 chainsaws come with a 44.7mm piston.