... 2.high quality with best price 3.certification of CCC,CE&ISO9001 4Manufacture solar vacuum tube 1,vacuum tube length:47/1500mm,58/1800 ... .2,vacuum tubes:15pcs,18pcs,20pcs,24pcs,30pcs3 ... -1800mm co-axial structure high borosilicate 3.3 glass vacuum tube with tube wall thickness of 1.6mm.Inner tank materialSUS304-2B ...