The product is a lightweight, portable, rechargeable detector. Designed to meet your detecting and hearing needs by providing advanced detecting functions and a full range of sound of the fetal heartbeat. Mainly used to detect the fetal heartbeat rate (FHR) and the sound of the fetal heartbeat (SFH). 100B fetal doppler can meet the routine examination requirements of obstetricians, midwives and pregnant woman themselves. With backlight and audio playback, it also has an audio output which can be connected with earphone or recorder.