The device is suitable for use after the 12th week of pregnancy. SpringBud Fetal Doppler Heartbeat Detector Portable Ultrasound Baby Heart Rate Monitor LCD Backlight CE 3Mhz Probe Portable Pocket Fetal Doppler Accuracy of testing, fetal sounds are very clear Small size / Easy to operate / Energy saving Sensitive Probe Large probe with high sensitivity, no radiation, more safe, and convenient measurement. With headset earphone. Listen And Record Fetal Sounds Now you could listen and record your unborn baby's heart sounds beat at your comfortable home. Enjoy the amazing experience of hearing your baby's heart sound and hiccups, even record them to share with families and friends in the future.