● Enough length and width for high-efficiency heating● Made of high-grade PE for long-lasting use● Work well in the temperature between -20°C and 90°C (-1℉and 194℉)● Good heat absorption for energy saving● Allow you to swim with comfort in all seasons● Firm connection avoids leakage● Can be installed on the ground inclined frame or roof● It is not recommended to use on the asphalt shingle roof