Solar Sun Rings are a passive solar swimming pool heating device made from two sheets of heavyweight U.V. resistant vinyl. The upper clear layer holds insulating air and focuses sunlight on the blue colored lower layer. The blue layer absorbs about 50% of the sunlight and converts it to heat. The balance of the sunlight is allowed to pass through into the pool for deep water heating. Solar Sun Rings were designed to be compatible with automatic pool cleaners. Neither water nor pool chemicals can evaporate through the Solar Sun Rings two layers of heavyweight vinyl. You will save water and chemicals about equal to the percentage of the surface covered. Solar Sun Rings may be used on all chlorine or salt water system pools, whether in ground or above ground.