How about BITS Fetal Heart Monitor

This brand is quite good.

BITH's Fetal Heart Monitor is a very useful medical device which is mainly used to monitor the heartbeat and fetal movement of the fetus in the mother's body. The device also provides important information to help doctors assess the health of the fetus and take necessary measures in a timely manner.

BITS's fetal heart rate monitors are more portable and easier to use than other brands, which is helpful in preventing and treating fetal complications and pregnancy risks.