optionally. The range of oxygen concentration is from 21% to 100% and is adjusted separately with the flow. ◆The range of flow rate is 5L/min~I 5L/min. ◆The MAX-P and PIP are controllable and accurate. ◆The PEEP is constant and accurate. ◆Simple operation and flexible application. ◆The output pressure will not be influenced by operator's lack of experience, training, attention and relaxation. ◆Replacement for temporary breathing support.