Argon Gas
CAVITIES BETWEEN GLASS PANES IN EKO PLUS WINDOWS ARE FILLED WITH ARGON GAS OF 90%
a poor conductor of heat = provides great insulation
naturally occurring in the environment noble gas which is a colorless, odorless and it is totally inert to other substances
does not contain any ozone depleting chemicals, it is not harmful to plant and animal life and is not listed as a marine pollutant.