The Husqvarna 544100102 Lawn Mower Expansion Tank Rider Extended helps manage coolant expansion and recovery for reliable engine cooling system performance. Designed as a replacement expansion tank, it fits compatible Husqvarna rider mowers to provide a reservoir for excess coolant during temperature fluctuations. It works by collecting expanding coolant as the engine heats up and ret... https://www.wholetoolbox.com/husqvarna-544100102-lawn-mower-expansion-tank-rider-extended