Dual Port Manometer and Pressure Switch TesterThe SDMN6 dual-port manometer measures gas and static pressure and also accurately tests pressure switches by simulating a draft with an internal pump. A pressure switch is a safety device that prevents the furnace from running in anunsafe manner. The SDMN6 tests the pressure switch to determine if it is working properly, or if it is starting to fail which can cause the furnace to run in an unsafe manner. Plus, with the SDMN6 you can easily calibrate any adjustable pressure switch to manufacturers' specification, so there's no need to carry a large variety of pressure switches on your truck. The Dual Port Manometer has the ranges to measure gas pressure and the resolution needed to measure static pressure. Ideal for HVACR field service technicians, the SDMN6 can determine if the gas pressure coming into the house or out of the regulator are correct. The SDMN6 measures gas pressure up to 60" water column (WC) with a resolution of 0.1" WC. In addition, the unit measures both positive and negative pressure, which is used for measurement on vacuum control lines. The unit will take differential pressure readings and display the difference between P1 and P2 at all times in the lower right corner of the easy-to-read LCD. Four different measurement scales can be used: inches of water column, millimeters of water column, mBar, and PSI. The SDMN6 also has a zero adjust to zero out the meter in different ambient pressures. It has a hold button to hold the currently displayed reading. The auto-power-off function conserves battery life, but can be disabled if desired. In the static pressure mode, the unit can measure up to 2"WC with resolution to 0.010"WC, which enables a technician to measure small differences in air (or static) pressureIncludesSDMN6 - Dual Port Manometer and Pressure Switch TesterANC1 - Four Pocket Carrying CaseASP2s - Static Pressure ProbesRMA316 - Pressure TubesQuick Connect LeadsHoses and Y-splitterHoses with Brass Screw FittingsFeaturesGas, static, and differential pressureTest pressure switchesEasily calibrate any adjustable pressure switchGreat for diagnosing furnace performance.