Non-Pressurized Compact Solar Water Heating 1.Tube Size:58*1800 2.Outer tank diameter:480,500 3.Inter tank diameter:470,490 Non-Pressurized Compact Solar Water HeatingTube Size:58*1800Outer tank diameter:480,500Inter tank diameter:470,490Tube quantity: 10, 12, 15, 18, 21, 24, 30, 36 piecesAssistant tank capacity: 20 to 120L