sonotrax handheld Doppler can meet routine examination requirement of obstetricans,midwives,pregnant women and vascular.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. It has 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 ?2 AA Size Batteries ?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 timee15 hours Option: [SonoW] 2 MHz Waterproof Obstetrical [Sono3] 3 MHz Obstetrical [Sono4] 4 MHz Vascular [Sono5] 5 MHz Vascular [Sono8] 8 MHz Vascular