Eadn SD1-b Fetal heart Rate Doppler 3mhz probe, bluetooth built-in , new low noise version
Baby Sound C Digital Pregnant Pocket Fetal Doppler Monitor 2MHz 3MHz 8MHz Baby Heartrate Detector - China Fetal Doppler, Pocket Fetal Doppler | Made-in-China.com
FDA Approved SpringBud FD-350B Fetal Heart Doppler
Edan SD3.03 Fetal Doppler with Interchangeable Probes, OLED Display of FHR Readings, and Built in Speaker, Standard Configuration Includes 3MHz, Uses AA Batteries