onotrax handheld doppler can meet routine examination requirement of obstetricians, midwives, and pregnant women. it is a high performance model with fhr digital lcd display. it has three heart rate processing modes: real-time fhr display mode, averaged fhr display mode and manual mode. both of the models have audio output, and can connect with earphone or recorder with audio input. sonotrax has a slim, power saving and interchangeable ultrasound probe. feature: ■ easy to use ■ accurate fhr detection and lcd display ■ auto and manual counting ■ built-in speaker ■ automatic switch-off ■ battery energy indication function: fhr detection: speaker output/earphone output lcd display, five working modes: real-time fhr display mode, averaged fhr display mode, manual mode, continuous operation time≥240min