For use with the Testo 510, 435, or other micro manometer digital manometers to measure velocity pressure (the difference between static pressure and total pressure) in ducts. All have a 5/16" OD tube with inch graduation marks on both sides. They come with an air-velocity slide chart and direct-reading flow chart. Comply with AMCA (Air Movement and Control Association) and ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) specifications.
