Functional features: ★ Equipped with a built-in high-capacity lithium battery that can work for a long time, and equipped with an external lithium battery charger. ★ Adopting digital tube display, button operation, convenient and quick setting of parameter content. ★ The fetal heart rate intensity of the simulator can be adjusted, and the fetal heart rate value can be adjusted. ★ Can simulate changing simulated fetal heart rates of different volumes ★ It is possible to change the simulation of different fetal heart source depths