This is a compact indicating purifier for high-efficiency oxygen removal, suitable for use with chromatography carrier gas streams It removes oxygen to low-ppb levels, with an indicator that changes color from green to gray when adsorption capacity is depleted The adsorbent forms copper oxide in the presence of oxygen; no gas is generated The ZPure™ Glass O2 Filter is recommended as a downstream indicator for high-capacity purifiers such as the ZPure™ Dual or the stainless steel ZPure™ O2 Filter It can be used with non-oxidizing gases such as He, Ar, N2, H2 or CH4 The adsorbents are held in a heavy-walled inner glass tube, shielded by an outer clear plastic tube for increased safety Dual Seal Design: In this design the glass inner tube is protected by a sealed outer plastic tube This design provides extra protection if the glass tube were to fail, the gas system is still fully protected against leaks