NEVER BEEN USED Easy To Use, High Performance Baby Heartbeat Monitor . This fetal Doppler is high sensitivity, 0 radiation, convenient measurement. Large-screen LCD display readings more clearly. High sensitivity waterproof probe, 12~16weeks can hear fetal heartbeat easily. Using clear tuning chips, the sound is more realistic. Light and portable fetal monitor, built-in speaker and 3.5mm headphone socket with volume control. The fetal doppler monitor is a hand-held obstetrical unit, which is applicable to clinic and home for daily self-check by pregnant women.