... Within 3days 4.Manufacturer solar collector tube DescriptionVacuum tube58-1800mm co-axial structure high borosilicate 3.3 glass vacuum tube with tube wall thickness of 1 ... resistanceDia=25mmGuarantyWater tank for 5 years, tube and frame for 15 years1,vacuum tube length:47/1500mm,58/1800.2,vacuum ... of the water tank ,and the cold water sink to bottom,then heat by solar collector.so the whole system is ...