text: European Union Within the EU, valves with M26x2 outlet thread are recommended for cylinders with increased oxygen content. Regulators for use with these cylinders require compatible connectors, and are not directly connectable with cylinders for compressed air.
  Germany
  A nitrox cylinder is specially cleaned and identified. According to EN 144-3 the cylinder colour is overall white with the letter N on opposite sides of the cylinder. The fraction of oxygen in the bottle is checked after filling and marked on the cylinder.
  South Africa
  South African National Standard 10019:2008 specifies the colour of all scuba cylinders as Golden yellow with French gray shoulder. This applies to all underwater breathing gases except medical oxygen, which must be carried in cylinders that are Black with a White shoulder. Nitrox cylinders must be identified by a transparent, self-adhesive label with green lettering, fitted below the shoulder. In effect this is green lettering on a yellow cylinder, with a gray shoulder. The composition of the gas must also be specified on the label. In practice this is done by a small additional self-adhesive label marked with the measured oxygen fraction, which is changed when a new mix is filled.
  The 2021 revision of SANS 10019 changed the colour specification to Light navy grey for the shoulder, and a different label specification which includes hazard symbols for high pressure and oxidising materials.