glass tube 1.High borosilicate 3.3glass.the life can lasts ... more than 14years. 3.CE,CCC,ISO glass tubeVacuum tube:1,the pipes are made of advavced superconductive oxygen-free ... graceful appearance long service life and non pollution3,the evacuated tube with superconductive heat pipe is the most advanced product inthe ... and severe temperature6,High efficiency of heat absorption solar vacuum glass tube