A fetal Doppler is a machine used to listen to a baby's heartbeat and hiccups. It is a test that uses sound waves to check the baby's heart beat. it is a types of ultra sound that uses a handheld device to detect changes  in the movement that are translated as sound.

Portable Pocket Fetal Doppler

This fetal doppler is a hand-held obstetrical unit, which can be used in hospital, clinic, and home for daily self-check. It is specially designed for the pregnant woman to conduct daily inspection of Fetal Heart Rate (FHR) by themselves. 
It contains components of ultrasonic signal transmitter and receiver, analog signals processing unit, FHR calculating unit, LCD display control unit, etc.
The fetal doppler is a high-performance model with (fetal heart rate) LCD digital display. It has three work modes: Real-time FHR display mode averaged FHR display mode and manual mode. All three models have audio output and can be connected with earphone or recorder with audio input. It uses standard 1.5V DC alkaline batteries (2pcs).

Accuracy of testing, fetal sounds are very clearSmall size / Easy to operate / Energy saving