Designed exclusively for the HVACR field technician, Fieldpiece Instruments' SDMN5 Dual Port Manometer measures gas presure, static pressure and pressure differential. Technicians can check gas pressure before and after the regulator; find duct blockages and blower problems; and check vacuum control lines, combustion air proofing switches, pneumatic thermostats, and negative pressure gas valves. DIsplays positive and negative pressure. Includes a rugged rubber boot, hands-free magnetic hanger, and Min/Max data hold.— Fieldpiece Instruments