CFR / 
Title 21
 / Part 868
 / 
Sec. 868.5740 Tracheal/bronchial differential ventilation tube.
(a) Identification. A tracheal/bronchial differential ventilation tube is a device used to isolate the left or the right lung of a patient for anesthesia or pulmonary function testing.
(b) Classification. Class II (performance standards).