Features 1. Prince-200B fetal doppler monitor comes with a built in speaker. 2. It utilizes 3×AA batteries power supply with low power indication. 3. The fetal doppler monitor uses a LCD display with backlight. 4. It allows numerical real time display of FHR and trend waveform. 5. The adoption of DSP (digital signal processing) technology guarantees clinical level FHR results. 6. The fetal doppler monitor will automatically power off in one minute if no FHR signal is detected. 7. It offers audio and visual alarms. The alarm limits are adjustable.