To that end, engineers at Parker Hannifin Corp.'s Tube Fitting Div., Columbus (parker.com), have developed a full range of their Seal-Lok stainless-steel fittings (H2P ports) to handle 700-bar (10,000-psi) hydrogen applications. The fittings range from 1/4 to 3/4-in. and work with standard SAE connectors. O-rings, which are critical for sealing, can be made from one of three approved compounds. In addition to being suitable for high-pressure hydrogen, the port will also handle compressed natural gas at up to 350 bar (5,000 psi). The port meets European Integrated Hydrogen Project requirements, as well as Economic Commission for Europe's R110 regulations and ISO 15500 standards for onboard storage and delivery of CNG.