 It consists of a cuffed, double-lumen tube that is inserted through the patient's mouth to secure an airway and enable ventilation.Generally, the distal tube (tube two, clear) enters the esophagus, where the cuff is inflated and ventilation is provided through the proximal tube (tube one, blue) which opens at the level of the larynx.In the rare instance where the distal tube intubates the trachea, ventilation is provided through the distal tube.