This is a brand new top end kit for a husqvarna chainsaw! I'm not sure what model it is for but I believe its for a model 44 or 61 but not sure. I have tried to give good clear pics so you guys can figure it out for sure. I ordered this new for one of me saws and I don't have many. It does come complete but in the shuffle the piston ring is broken so it will need a new ring to be complete! Measuring across the top of the piston measures 1.729 inches which converts to 43.9166 in MM.