Recommended for ducts 10" and larger in diameter. Plainly inscribed inch graduations on both sides show depth of insertion at a glance—this helps you find the exact center of any duct and make an accurate traverse quickly. Tubes comply with AMCA and ASHRAE specifications. Test-confirmed unity coefficients. Life-time construction of 304 stainless steel. Suitable for use in temperatures up to 1500°F (815°C). Accurate readings when tip is directed within 15° of airflow. Static connection extends 31⁄2" to serve as guide for directing tip. Swaged tip, silver soldered connections.