Solar 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 borosilicate 3.3 GlassExternal PipeDiameter & Thickness dia.=47±0.5mm &=1.6mm,dia.=58±0.5mm &=1.6mmdia.=70±05.mm &=2.0mmInternal ...