... ISO9001,SGS high quality, competitive price OEM service solar water heaterhigh quality, competitive priceOEM serviceCCC,CE,SGS,ISO9001,Solar ... tank: Stainless steel SUS304, 0.4-0.5mmOuter tank: color steel, 0.31mm Vacuum tube: common \three-target; 47x1500 ... Water flow inside and complete a circulation on it own without given pressure, which is how the name comes from. color steel solar water ...