Horizon Floating Spa Covers protect your hard spa cover from corrosion, reduce overall heat loss, and prevent spa chemical evaporation. These lightweight and durable floating spa covers rest directly on the water under your spa's hard cover, protecting it from the gas created when spa chemicals burn and evaporate, while their moisture-resistant design reduces heat evaporation. These seamless Floating Spa Covers can be easily trimmed to fit any spa or hot tub and are a perfect solution to saving energy and money while preserving the life of your spa cover.