Pipes, tubes, hoses and fittings therefor, including valves, of metal; metal hardware; metal pipes; flexible tubes of metal; metal hose and pipe connectors; metal manifolds, couplings and adapters; metal hose and pipe couplings; metal mountings; spring-retracted metal hose reels, all of the aforementioned for use in or in connection with apparatus and instruments for conducting, switching, transforming, accumulating, regulating or controlling the distribution or use of hydrogen, also in liqui...