... 2.Anti-freezen & pressurized 3.10 years warranty Vacuum tube solar collecotr a. Module design, arbitrary combination, harmonize ... casing & red copper flow passage6) Glass tube: new trivalent element heat tube, borrosilicate glass 3.37) Solar working station8 ... 24-5818SC-H-30-5818Length of Tube1800mmOuter Diameter of Tubeφ58mmTube Quantity1518202430Manifoldcasing material,Aluminum Alloy,Thickness,1.8mm, ...