[ Plumbing fittings, namely, gas shut-off valves; plumbing fittings, namely, two-way gas valves; plumbing fittings, namely, gas bottle valves; plumbing fittings, namely, gas valves; ] gas regulators; regulating and safety accessories for [ water or ] gas apparatus [ and pipes, ], namely, pressure reducers and safety valves; flow limiters, namely, compressed [ and liquefied ] gases flow regulating apparatus in the nature of gas regulators; flow regulators in the nature of gas regulators [ ; ap...