Bubble Humidifier with 6 PSI - Black Lid The Bubble Humidifier helps prevent drying out of mucous membranes in your nose and mouth while using any Oxygen Concentrator. Designed with an audible-alarm pressure relief valve, these humidifiers warn you whenever an obstruction occurs meaning you will not suffer any lack of therapy! This 6 PSI model is designed for all applications, including use where longer lengths of tubing can increase back pressure. The jar and lid are constructed of break-resistant plastic, humidifiers also feature a durable plastic flow meter nut. Features For use with Oxygen Flows from 2 to 12 LPM Disposable, durable plastic Durable plastic flow-meter nut Holds 500 ml water Max Flow Rates 12LPM - Up to 20 ft of oxygen tubing 10LPM - 21-30 ft of oxygen tubing 9LPM - 31-40 ft of oxygen tubing 8LPM - 41-50 ft of oxygen tubing Included in the Package (1) Bubble Humidifier Bottle