Product Description: 1.[High Accuracy & Resolution]: The digital manometer can measure 2.999Psi/ (0.001 resolution) with accuracy 0.3% in full scale. 2.[Dual Tube Connectors]: Comes with Positive & Negative pressure tube connectors, which can easily measure differential pressure with its dual input probes. 3.[12 Measure Units Available]: 12 kinds of units for your needs, including Kpa, Psi, kgcm2, ozin2, Bar, mbar, inHg, mmHg, inH2O, ftH2O, cmH2O, Pa 4.[Max & Min Button, Back-light, Data Hold, Auto-off]: The AUTOOL digital manometer is tailor-made with all of these useful features for your work requirements Great tool for homeowners and handymen. 5.[Wide Applications]: Best used for HVAC, pneumatic control, medical equipment, gas appliance service and installation, laboratory testing, computer peripheral. Easy to use and accurate with a large display. Specifications: Measuring range: 20.68Kpa/2.999PSI Measure Accuracy: 0.3%FSO (25) Repeatability: 0.2% (Maximum +/-0.5 FSO) Linearity/hysteresis: 0.29 FSO(25) Response: Typical 0.5s Up overload indication: Err0 Down overload indication: Err1 Operating temperature: 0~50 Storage temperature: -10~60 Power Supply: 9V battery no include Package includes: 1pcs* AUTOOL Digital Manometer main unit 2pcs* Tubes 1pcs* Fitting 1pcs* Package box 1pcs* User manual