Features:
    Pocket design,easy and conveniently to use
           High quality loudspeaker,clear timbre,volume can be adjusted
           Sound alarm function when FHR is not in normal range
           Two FHR modes:real-time and average
           Big LCD for dynamic display of FHR and battery energy
           Matching different battery:AA battery,9V battery or rechargeable battery
           Continuous working time ≥8 hours
           Rest automatically no FHR signal,Automatic switch-off function
           Backlight function,buitlt-in safeguard of circuit
           Built-in loudspeaker:Audio output can connect recorder and earphone
Specification:

Display
LCD Size:37mmx23mm

 
Ultrasound
Ultrasound Emitting Frequency:                                                                           2.5MHz
Ultrasound Emitting Power:                                                                                 <10mW/cm²
Overall sensitivity at the distance 200mm from the face of the tube
(doppler frequency 300 50Hz,target velocity 10cm/s~40cm/s):                       ≥90dB
Spatial-peak temporal-peak acoustic pressure:                                               <8.6kPa
Output power:                                                                                                          <26mW
Effective area of the ultrasonic transducer for active element:                       1.57cm²20%
The acoustic coupling medium for normal use:                                                ph:5.5 - 8, Acoustic impedance

FHR Performance
Automatic FHR test range:                                                                                50~210bpm
Heart rate alarms:                                                                                            <100, or>160bpm
Resolution:                                                                                                        1bpm
Accuracy:                                                                                                           1bpm
Audio output power:                                                                                         1W
Audio out socket:                                                                                              Φ3.5mm

Rechargeable battery
Battery voltage:                                                                                                3.6V/9V/3XAA
Chemist                                                                                                             Nickel metal hydrogen. Refer
                                                                                                                          to local regulations
Compatibility:                                                                                                    Compatible with product
Battery capacity:                                                                                               2 hours in 9V/170 mAH
                                                                                                                          or 7 hours in 3.6V/1000 mAH
Battery charging time:                                                                                       2 hours for 9V/170mAH,
                                                                                                                          or 8 hours in 3.6V/1000 mAH
Charging time:                                                                                                   Maximum 10 hour
Battery life:                                                                                                        2.5 year/300 cycle of battery
                                                                                                                          charging/discharging
                                                                                                                          whichever comes first
Battery weight:                                                                                                  1lb or 3 oz
 
AC Power Supply
Input:                                                                                                                230V, AC, 50Hz, <20VA
Output:                                                                                                             12V, DC, 300mA

Dimensions 
Physical Size:                                                                                                     97mmX37mmX132mm
Weight:                                                                                                              0.3Kg(including battery)