Material: carbon steel, alloy, aluminum alloy and Bare tube size: OD25.4mm-OD76.2mm Our fin tube,spiral fin tubeSpecification:Material: carbon steel, alloy, aluminum alloyBare tube size: OD25.4mm-OD76.2mmFins Pitch:4mm-30mmFins Height:5mm-30mmFin thickness:0.3-3mm The size of the finned tube can be discused at the client's requirements.