... (TOCO), FM and Maternal ECG, NIBP, SPO2, PULSE, Built-in rechargeable battery, thermal printerOptional: Dual TEMPTechnical ... 85%Ultrasonic Probe: (Fetal Heart Rate)TypeType B proof, dirctional, using pulse doppler systemWorking frequency2.5 MHzTransmitting power ... Resolution1%Accuracy±2% (80~100%)±3% (60~79%) PULSE RATERange0 ~ 254bpmResolution1bpmAccuracy±1bpm or ±2%, whichever is greaterAlarm ...