AGSS terminal units take the principle of positive pressure jet to put the waste gas away through the negative pressure zone formed by the positive pressure of compressed air. It is a more advanced, safer and more stable second-generation waste gas recovery and discharge technology. Compared with the first-generation negative pressure suction AGSS terminal units, there is no danger caused by evacuation of the breathing gas in the patient' s lungs, and no expensive anesthetic gas is wasted, thus achieving the requirements of low operating costs and no maintenance.