Product details:

Roll-up manometer measures static, vacuum, and differential pressure of air and gas in fan and blower tests, gas pressure evaluation, and calibration applications Acrylic plastic top, connectors, and over-pressure traps and vinyl tubing for use with air and gas Calibrated in inches of water using water for use with mercury or water with fluorescein green concentrate measuring fluids (sold separately) Flexible spring-steel scale mounted between columns eliminates parallax reading errors, and 2" sliding zero adjustment provides zeroing capability Maximum intermittent total pressure of 50psi, and vacuum up to 20" Hg Dwyer Slack Tube Manometers are as accurate as the finest laboratory "U" gages - yet they are made to roll up compactly for easy carrying and to withstand rough usage. Simply unroll the Dwyer Slack Tube Manometer and set up to read static pressure, vacuum, or Differential Pressure. Magnetic clips hold it firmly to any steel surface or hang it on a nail. Dwyer Slack Tube Manometers cover a wide range of pressure readings from 4-0-4 inches up to 60-0-60 inches. Use them in determining velocity and static pressures, for leakage, fan and blower tests, calibrating control devices, checking gas pressure and many other applications. All models have flexible vinyl-plastic columns and flexible spring steel scale calibrated in inches of water using water; and inches of mercury using mercury. Scale is center-mounted between columns to eliminate parallax error and has a full 2" sliding zero adjustment. All Dwyer Slack Tube Manometers feature exclusive molded nylon tubing connector assemblies with rapid shutoff design in an acrylic plastic top. One turn counter clockwise and the instrument is ready for use. Another turn seals the tubes completely. Molded all-nylon construction makes this assembly corrosion-proof, leak-proof and practically unbreakable. Tubing connectors extend horizontally allowing 360° freedom.