... length:20m(bottom),15m(up);or any other solar water heater:Product ModelXK-SPVacuum tube58-1800mm co-axial structure ... temperature ≥-35Frame optional angle0°,25°,38°,45°Capacity of water tank80L,100L,150K,200L,250L,300L,400L,500L. 40L/ ... hours48-72 hoursHailstone resistanceDia≤25mmWorking pressureTest pressure ≤10 pa, safety work pressure≤0.7MpaEfficiencyDaily efficiency:≤55% (≤42% in winter)Sample ...