Esso Research and Engineering Company has already devised a system for clearing urban roadways that is reported to be cheaper than under-pavement steam or electric coils.
埃索研究工程公司已经开发了个郊区道路清理系统，据报道会比人行道下的蒸汽电力圈更为便宜。
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The coil products including: carbon steel coils, stainless steel coils, aluminum brass coils and steam drain valve group.