... Vacuum tubes 1.Excellent performance of absorbing, but low heat loss 2.Excellent resistance of burst. 3.15years uselife Solar Vacuum ... years in USA,Germany, Australia, France, Japan, Canada, China ,the UK, Chile, Peru, Brazil, Russia and so ... DC magnetron sputtering technology, makes the highest of vacuum tube working temperature as high as 300°C, ... Specifications 1800*58mm/1500*47mm Solar vacuum tubes