Official BabyDoppler Sonoline B Fetal Doppler Excellent Pre-Owned Condition Instantly Detect Baby's Heartbeat: The device is equipped with a highly sensitive 3 MHz probe, designed to help you hear your baby's heartbeat as early as 12 weeks into your pregnancy. ​Built-in Speaker & Headphone Jack: Listen to your baby's heartbeat directly through the built-in speaker, or use headphones for a more private experience. ​Back-lit LCD Screen: The clear, back-lit screen displays the fetal heart rate (FHR) in beats per minute (BPM), providing a visual reading in addition to the audible sound. ​Intelligent Noise Reduction: Advanced technology minimizes static and background noise for a clearer, more optimal sound. ​Lightweight and Portable: The compact, pocket-sized design makes it easy to use anywhere, whether you're at home or on the go. Sold as Pictured. Includes batteries and gel. Smoke and pet free home.