... high-efficiency 3,Modular design and auto-operation 4,Multifunction Solar water heater features:1.Modular design, arbitrary combination,harmonize with the building ... foam and has a good effect of temp. preservation.c, Water tank: All SUS-2B materiald, Glass vacuum tube: new ... borosilicate glass 3.3e, Heat pipe: anti-freezing >-35°Cf, Water capacity:150L 200L 300L 500Lg, Heat preservation time:72Hr-80Hr ...