Handheld Digital Manometer, Maximum Pressure 20 psi, Minimum Pressure 0 psi, Pressure Accuracy +/-0.5 Percent, Process Connection Size 1/8 in, 3/16 in, Process Connection Type Hose Barb, Includes Batteries Yes, Digital Display Features 4 Digit LED, NIST Traceable Certificate No, Series 477AV, Maximum Air Velocity 94,220 fpm, Pressure Units psi, Air Velocity Accuracy +/-0.5 Percent Full Scale from 60 to 78 Degrees F, +/-1.5 Percent Full Scale from 32 to 60 Degrees F and 78 to 104 Degrees F