... ., Ltd. Designs and manufactures all kinds of finned tubes. 1, finned tube function: heat transfer;2, the fin-tube type: DR (extrusion type), L (winding ... (wound type, high frequency welding), copper (winding type).4, finned tube specifications: 1, base tube: OD16, OD19, OD1 ", OD38; 2, fin: OD34, OD44 ...