Salter Labs Bubble Humidifier 350cc, Dry, with 3 PSI Safety Pop-off AlarmAll new 360® rectangular diffuser ports provide quiet operation with low system back pressure and 3 psi pressure pop-off, alarm. New dome lid design incorporates refinements, resulting in high performance Ideal for use with all oxygen sources: concentrator, liquid, tank, wall outlet. 360o Rectangular Diffuser ports provide quiet operation with low system back pressure. Dome lid design combines high performance with rugged durability. All Salter bubble humidifiers provide dependable, cost-effective performance. Disposable Humidifiers from Salter Labs are single patient use products designed and engineered for long term durability and complete patient satisfaction.360° molded, low resistance, high output diffuser head design.Connecting tower design.Large, quad wing nut connector.Audible pop-off alarm 3 PSI .Jar permanently etched, large print minimum/maximum water level markings.Easy seal, translucent, double helix thread jar.