Oxygen Purity: Medical oxygen cylinders usually contain pure oxygen (99.5% or higher). Industrial oxygen may have slightly lower purity but is generally also very high.Pressure: Oxygen is stored in cylinders at high pressures, usually around 2, 000 to 3, 000 PSI (pounds per square inch). The pressure allows a significant amount of oxygen to be stored in a relatively small cylinder.Volume: The volume of oxygen in a cylinder is usually measured in litres. For example:A small portable cylinder might hold around 170 litres of oxygen.A standard D-size cylinder might contain around 340 litres.Larger H or M-size cylinders can hold thousands of litres, around 7, 000 to 10, 000 litres.Physical State: The oxygen in the cylinder is in a compressed gas form. When released, it expands to provide a breathable gas to the user.Cylinder Sizes: Oxygen cylinders come in various sizes, from small portable ones (used in ambulances or for home care) to large stationary cylinders used in hospitals. rentet available