Solar Water Heater: 1) Glass tube: 47 x 1500mm/58 x 1,800mm 2) Inner tank material: SS3042B food grade 3) Out tank material: power painted steel/aluminum magnesium sheet with metal painting 4) Out tank diameter: 420mm 5) Frame material: aluminum with anti-oxidation treatment 6) Insulation: 50mm polyurethane total forming with pressure and high density 7) Available sizes: 18, 20, 24, 36 tubes with tank capacity of 117L to 230L 8) with 5L Assistant Tank Customized is available