The glass adapters that can be used in ultra-high vacuum and high vacuum environments come in two types: closed-end and open-end. The bonding of metal and glass can be done with Kovar (magnetic) & 7052 glass, Kovar (magnetic) & 7740 Pyrex, SUS304 (non-magnetic) & 7740 Pyrex, SUS321 (non-magnetic) & 7740 Pyrex, etc. Additionally, the material of the bellows is SUS321 (non-magnetic). Custom sizes for glass tubes are also available. Please consult us.