... glass tube 1.High borosilicate 3.3glass.the life can lasts 15years. 2.Manufacturer for more than 14years. 3.CE,CCC,ISO glass ... tubeVacuum tube:1,the pipes are made of advavced superconductive ... long service life and non pollution3,the evacuated tube with superconductive heat pipe is the most ... temperature6,High efficiency of heat absorption solar vacuum glass tube