Measures air pressure of the single pipe or differential pressure of 2 pipes. Has 11 selectable units of measurement kPa, psi, kgfcm2, ozin2, bar, mbar, inHg, mmHg, inH2O, ftH2O, cmH2O. Application: HVAC/R refrigeration air-conditioning industry used to measure the pressure difference Measure negative pressure setting to ensure indoor air pests will not pollute the air in the outside world Measure the positive pressure Computer peripheral equipment pneumatic control Features: Differential, Negative, Positive pressure measurement Max / minimum / Average reading record function Large LCD backlit dual display Zeroing, offset and data compensation Low battery display and Auto power off set up function Data Hold and Error code Functions Over/ Under range indicator User can re-calibrate the meter at anytime Specifications: FUNCTION RANGE RESOLUTION kPa ±13.78 0.01 psi ±2 0.001 kgfcm² ±0.14 0.001 ozin² ±32 0.01 bar ±0.137 0.001 mbar ±137.8 0.1 inHg ±4.07 0.001 mmHg ±103.4 0.1 inH₂O ±55.35 0.01 ftH₂O ±4.613 0.001 cmH₂O ±140.6 0.1 Accuracy: ±0.3% FSO (at 25°C) Repeatability: ±0.2% (Max+0.5%FSO) Linearity/Hysteresis: ±0.29% FSO Response Time: 0.5 Seconds Over Range Display Indicator: Hi Under Range Display Indicator: Lo Operating Conditions: 0 ~ 50°C(32 ~ 122°F) Storage Conditions: -10 ~ 60°C (14 ~ 140°F) Power Supply: 9V battery Size: 165 x 80 x 45mm Weight: 220g (battery not included) Set Includes: 1 x Digital Manometer 2 x Plastic Hose 1 x Metal Connector 1 x Carry Pouch 1 x 9V battery English Manual