A device used in conjunction with certain endoscopes (e.g., a rigid or flexible bronchoscope) to provide an atraumatic, direct measurement of the lumen and length of a pulmonary stricture for the indication of correct tracheobronchial stent selection. It is inserted through the working channel of the endoscope through which the physician views the site whilst operating this device to make the required measurements. It consists of a solid metal wire in a plastic sheath that terminates in expandable sizing arms at the distal end. The arms are operated by the physician through a syringe-like activation handle and a built-in indicator relates to the lumen diameter. This is a single-use device.