Air meter with detachable probes measures air velocity in fpm Includes a slide rule calculator for determining static pressure in inches of w.c. Dual-scale shows low- and high-range readings and has red graduations for distinct readings Made of hard plastic to resist breakage and provide a clear view of the scale Includes return grille probe, supply grille probe, angle connector, rubber tubing, air velocity calculator, pipe cleaners and nylon bristles for cleaning, carrying case, and instructions