SonoTrax Series Ultrasonic Pocket Doppler Easy- to- use Compact design Interchangeable waterproof probe Built-in audio recorder Large backlight LCD display Accurate FHR detection with high-fidelity sound effect Support waterproof probes for both obstetrical and vascular usage Auto, Average and Manual working modes Various power supply solutions Automatic power-off to save power Support 2MHz,3MHz,4MHz,5MHz,8MHz waterproof probes