PoolTree System -- Above Ground Pool Winter Cover Support System - for Round Pools up to 28' The industry's only self-cleaning winter cover support system for above ground pools! When used with a mesh (porous) cover, the System eliminates the need to scoop leaves, pump off the cover, or dump dirty water into the otherwise clean pool. Solid covers will require pumping. The patented supports flex and retract under load, reducing stress on your pool, and constantly adjusting to keep your pool cover out of the water. This allows the cover to dry, which enables debris to blow away. Simple, innovative design. Pool openings and closings have never been easier! Can be used with any cover. Mesh (porous) is recommended for best results. (COVERS SOLD SEPARATELY)