Must have product. Saves lots of money and creates comfort of lifetime. We live in San Diego, the weather for past 2 weeks was between 57 F at night and max 72 F during the day, partly cloudy. Our pool is free form approx. 36' x 18' and 5ft deep. We shaped solar cover to fit in the pool. Before using solar cover pool was loosing 2" of water per week, temperature would vary from 78 F in the morning to 82 F by the end of the day. After using cover for one week with 3 hours gap, when letting kids play, the temperature reached 95 F and it may continue to grow. It costs $250 of propane to once hit the pool by 15 degrees and it cools back down in 2 days. With solar cover pool is always 15 F warmer, that is about $150/day if one would require to do the same using propane heater. On top of it, there was no noticeable water loos due to evaporation ( saving of $50/week ). This is a great product to save on water bill, achieve 15 F increase in temperature, and extend pool season by 2-3 months. I previously installed water solar panels of size 22' x 16' and that provided 3 F increase in peak temperature, but it will drop to same base during the night, and it would not prevent evaporation. This cover is a true magic and in one month it pays off just by saving on water bill. The cover seems strong enough to last for many years.