SonotraxB handheld Doppler can meet routine examination requirement of obstetricians, 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 timeí¦15 hours Option: [SonoW] 2 MHz Waterproof Obstetrical [Sono3] 3 MHz Obstetrical, Waterproof [Sono4] 4 MHz Vascular, Waterproof [Sono8] 8 MHz Vascular, Waterproof