Solar Sun Rings Solar Pool Heater (10) Solar Sun Rings are passive solar swimming pool heating devices, constructed from two layers of U.V. resistant vinyl. The upper clear layer directs the suns rays onto the bottom blue layer which absorbs about 50% of the sunlight, converting it to heat. The remaining sunlight filters through the ring into your pool water. Do not over inflate. Do not use as a flotation device. 10-Pack