The device is suitable for use after the 12th week of pregnancy. SpringBud FD-200B Fetal Doppler tracks baby’s heartbeat with 2MHz Probe by using the latest technology. It allows new moms to hear the heartbeat of their babies in an easy way and reduce anxiety. It comes with an LCD screen, built-in speaker and headphone jack. The LCD screen displays the battery status, heart rate in BPM (Beats Per Minute). Features: Big LCD Display with back light Built-in speaker ensure high-fidelity, clear sound Compatible with both earphone and speaker (Earphone NOT included) High sensitivity Doppler probe with Low ultrasound dosage Auto Power-Off function