Made of premium low density polyethylene 400 Micron this solar pool cover is extremely durable and can efficiently and effectively distribute the heat to the water. It allows the sun's heat to penetrate to the pool; increasing the temperature in the water as well as can significantly reducing water evaporation. Also it helps in keeping the pool clean; reducing maintenance time and costs for filtration and pumping. Maintaining your swimming pool will no longer be expensive get the best of natural resources and save money on chemicals and water! What so special about the Blue Top with Silver Underside design? It is especially designed for cooler climate countries such as Australia. The design allows the sun rays to penetrate the pool easier and faster. It also helps keep the heat in the pool for a longer time.