Ultrasonic frequency: 2.0 MHz±10%
Ultrasonic intensity: ≤10mW/cm2
Comprehensive Sensitivity: ≥90dB
FHR range: 60--210bpm(±2bpm)
FHR alarm range: ≤100bpm or  ≥160bpm
Isptp: ≤0.1MPa
Adapter input voltage: AC 110V±10% 60Hz / 220V±10% 50Hz
Rechargeable battery input voltage（no load）: DC 12V±1V
Maximum audio output intensity: ≤0.5W
Doppler frequency: 100--3000Hz
Static continuous working time: ≥4h
Automatic Dormancy time limit:1 minute
Working temperature: 10-40℃  
Atmospheric pressure: 86--106kPa