Specifications：
Ultrasonic frequency：2.0 MHz ± 10 %  (C.W.)
FHR display range：  60 – 210 BPM ( ± 2 BPM ) 
FHR alarm range：  ≤ 100 BPM  or  ≥ 160 BPM 
Battery：9.6 V Ni-MH rechargeable batteries 
Adapter input voltage： 220 V ± 10 %  50 Hz ± 1 Hz ,  (or  AC  110 V ± 10 %  60 Hz ± 1 Hz )
Adapter output voltage：DC 12 V ± 1 V
 Maximum audio output intensity：≤ 1.0 W
Automatic Dormancy time limit: ≥ 1 minute 
Static working time： BF-500B ≥ 4 H 
Normative collocation:
charger, gallus, portable soft handbag, 60 g Gel.
Packaging collocation:
Single unit dimension:19.5 x 16.5 x 6.5 (cm); Gross Weight: 0.85 kg
20 pcs / carton dimension:44 x 36 x 42 (cm); Gross Weight: 18 kg