It mainly consists of gas pressure, gauge, pressure reducer, safety valve, flow tube, flow control valve and humidification bottle. ARG Oxygen Flowmeter is durable, accurate, easy to use, and dependable. Oxygen Flowmeter is a pressure compensated flowmeter that delivers an accurate prescribed flow to patients from the gas source. The Inner flow tube scale is clear and simple to read.Oxygen fine adjustment valve with rotameter & humidifier bottle. Incorporates durable impact resistant polycarbonate outer and metering tubes for maximum durability. Durable chrome-plated machined brass body provides high durability and long life. Glass flow tube assures consistent readings. Precision control valve for accurate flow control. Oxygen flowmeter is safe, durable and accurate. Specially designed metal knob Specially made spindle for the adjustment. Easy to use. Inner flow tube scale is clear and simple to read.