Feature: Integral design of probe and host. Ultra-thin ,portable,smart ,and cosmetic Headset design allow the expectant mothers to listen the fetal heart sound at the same time High sensitivity of ultrasound transducer High precision FHR LCD digital display Ultra-low ultrasonic output intensity ,far below the requirement of national standard, to ensure the safe use, and with high safety quality. Ultra-low energy consumption,two AAA alkaline batteries can meet loong time detecting. Four color