Ionex Type Ag400 is a synthetic silver-exchanged zeolite for gettering hydrogen from vacuum spaces of cryogenic apparatus, selective removal of halogens from gas streams and as a hydrogen/oxygen recombined catalyst. This inorganic alumina silicate material contains supercharges within its crystalline structure which are especially large and uniform in size. These cavities and their large entrances (pores) allow extremely large capacity for trapping contaminants and maximum utilisation of the exchanged silver cations