... Split Pressure Solar Water Heater:Vacuum tubes assimilate the advance 12 layers of spattering deposit of rivalent element technology, high ... up to 400 degree of idle sunning, performing a strong heating ability, Certificate, CE, CCC, ISO 9001, Solar ... Automatic controllers can be applied to these systems6) Electrical heating element is optionalSpecifications1) Vacuum tube counts 15,16,18,20 ...