The Dwyer 166T Telescoping Pitot Tube is a unique air flow sensor which can quickly and easily be adjusted for any duct insertion length from 11.5 to 36 inches (29.2 to 91.4 cm). Now, this single compact unit can replace up to 5 conventional fixed length Pitot tubes. For even greater convenience, the 166T is securely protected by a custom fitted polyethylene carrying case. Telescoping sections lock in place as they are extended, enabling use of the handle grip to gauge proper alignment of the tip within the airstream. Stainless steel construction resists corrosion. Hemispherical tip has 1.0 flow coefficient, and is 1/8" in diameter (3.2 mm). Its largest section is 3/8" (9.5 mm).