group.com, Copper Tube Materials: No theoretical limits.'LL' Finned Tube Manufactured in the same way as the 'L' fin type except that the fin foot is overlapped to completely enclose the base tube thereby giving excellent corrosion resistance. This type of tube is often used as an alternative to the more expensive extruded type fin in corrosive environments. Maximum Working Temperature: 180℃ Atmospheric Corrosion Resistance: Acceptable Mechnical Resistance: Poor Fin Materials: Alu