... Machine-expanded type E. Spiral-finned typeTechnical Ability1) Fin specification for A type: L60*W27, L77*W27 ... , holes distance 25mm2) Fin specification for B type: Width 50mm or 60mm, ... 11*19.05 (22 equilateral triangle shape)3) Fin specification for D type: O.D9.52 copper ... tube, holes distance 25mm*25mm (square shape), fin pitch:4.2mmPerformance1) Surface: Anodic oxidization or dip ...