1. clear fetal heart sound: high performance clear fetal heart sound. 2. lcd display: multi-parameter working mode and fetal heart rate display, clear fhr (fetal heart rate) display. 3. high sensitivity: medical grade, high sensitivity waterproof probe , no radiation to detect, low ultrasound power, safer to the fetus 4. compatible with both earphone and speaker (earphone not included) 5. perfect to listen and record your unborn baby's heartbeat when she is 12 week above. 6. lightweight and easy to carry, you can share your joy - a healthy and strong heartbeat with your lover, families and friends, whether you are at home or out.