Gas Flowmeter Oxygen Pressure Reducing Regulators Valve is made of metal. Standard production workshop, with gas cylinder pressure display, pressure relief valve and humidification bottle interface, safe and hygienic, durable. Designed with a metal core and a copper filter those can filter impurities and clean the gas for your peace of mind. Reasonable structure, with strong operation, strong versatility and strong interchangeability. The oxygen inhaler humidification bottle has a muffler to reduce noise.