... vacuum tube 1)ISO9001:2000,CE,CCC,SGS 2)Specific Absorption:92%---96% 3)reliable quality,reaonable price Original and high quality three-layer solar vacuum ... tubesThe structure of inner tube SpecificationsStructure All-Glass Double Tube Co-Axial Structure Glass High ... ,1900mm,2000mm,2100mm Absorptive Coating Property Three layers of Magnetron Sputtering Plating.Cu/ ...