solar collector tube 1,reliable company for 12 years 2,large produtivity and good quality 3,good service ,competitive price solar evacuated tube ,solar evacuated tube , glass tube,system tube,solar collector tubeCertification:ISO9001:20001.Vacuum Tube's description 1 .External pipe diameter :47mm/58mm/70mm Internal pipe diameter:37mm/47mm/58mm 2 .Thickness:1.6mm/2.0mm 3 .Length:1500mm/1600mm/ ...