Solar Water Heater Material Vacuum tube Diamater: 47mm-1500mm, 58mm-1800mm 58mm-2100mm spacefilight vacuum heat collecting tube. Material of inner tank: SUS304-2B stainless steel with 0.4mm thickness Material of outer tank: SUS-2B stainless steel with 0.4mm thickness. Copper coil: The diameter is 12mm, thickness is 1mm. Heat preservation: Imported polyurethane foam with 55mm thickness. Specification: 58mm*1800mm Material of support: Stainless steel profiled bar with 1.2mm thickness orn galvanized steel plate wqith plastic spraying. ...