T-fitting sold by National Medical Ltd. is a kind of medical on-airway adapters made in the United States. It can be used in a lot of occasions, and it is mainly applied to ETCO2 sampling in National Medical Ltd. when intubated patients is sampling CO2, the T-fitting can be connected to the pipe of anesthesia machine or breathing machine. Then the extended sampling line sends a little of gas to a monitor to survey. T-fitting can be reused (actually it is disposable in some developped countries). Before it is reused, it must be disinfected. Once the connector is aging due to long-time disinfection, it must be replaced immediately.