TSI Model 8025 fit test adapters let you test the integrity of an individual's assigned respirator while also verifying donning competence and facepiece sizing. They reduce hygienic concerns of using a shared test respirator because the individual uses his or her assigned respirator. Since the fit test adapter components that are exposed to exhaled air are disposable, there is no need to sanitize between fit tests. The fit test adapter connects between the respirator facepiece and the filter cartridge. A small sample tube inside the adapter passes through the respirator inhalation valve and is firmly positioned via a small suction cup and clip so that a sample can be drawn directly from the breathing zone of the respirator. The adapter uses its own inhalation valve, so the respirator can function normally while the original valve is temporarily rendered inoperative by the sample tube.