Midwest Canvas MWC2440R In-Ground Rectangle Mesh Winter Cover, 24 by 40-Feet Mesh winter covers for in-ground pools are made with finely woven black polyethylene Allows water to pass through while trapping leaves, twigs and other debris The fine mesh design allows snow melt and rain to gradually fill your pool These covers can be used year-round in more moderate climates for day-to-day maintenance Comes in rectangle shape; measures 24-feet width by 40-feet length