... capacity can be from 1000L-30000L Split Pressure Solar Water Heater:Vacuum tubes assimilate the advance 12 layers of spattering deposit ... rivalent element technology, high borosilicate glass, gradual change of SS-C/CU selectic complex absorptive coating, through the inner layer , ... Electrical heating element is optionalSpecifications1) Vacuum tube counts 15,16,18,20,22, 24,26,28,302) Angle 38/453) ...