What is the high flow rate of portable oxygen cylinders equipped on airplanes? What is the low flow rate?

Portable oxygen cylinders equipped on aircraft have a high flow rate of 4 liters/minute and a low flow rate of 2 liters/minute. Portable oxygen cylinders are used for swimming medical assistance in the airplane cockpit during flight. Each oxygen cylinder is an independent oxygen system. Most of the portable oxygen cylinders are high-pressure oxygen cylinders, which are inflated to 1,800 PSIG at 70° F. The cylinders are equipped with a pressure gauge, which indicates the pressure of the cylinder, as well as the amount of oxygen in the cylinder. A shut-off valve is used to control the supply of the high-pressure oxygen cylinder to the head connection assembly. The oxygen cylinder head connection assembly contains pressure regulators that adjust the pressure and flow rate to the oxygen mask. The shut-off valve is turned clockwise to close and counterclockwise to open. Oxygen will only be retained in the oxygen mask if the oxygen mask connector is inserted.