GrayWolfs PIT-504 pitot static tube when connected to auto-zeroing differential pressure (ΔP)sensor gives a unique combination that helps in accurate measurement of air velocity/volume airflow over a wide range. A variety of other standard pitot tubes can also be used.Ellipsoidal tipped pitot-static tubes measure airspeed in ducts & stacks and calculate volume flow rate when used with GrayWolfs AdvancedSense™,WolfPack™, Zephyr or IAQ Surveyor Pro instruments installed with ΔP sensors or PIT-504 with alternate brand ΔP meters. GrayWolf pitot-static tubes are available in fixed lengths of 12, 19 or 39 inch.Other products include a versatile 4 stage extendable pitot tube,supplied with case and accessories.