Portable Fetal Doppler with Speaker and Backlit LCD Display. This handheld Pocket Fetal Doppler for pregnant woman into 12 weeks of pregnancy to safely check and listen to the fetal heart beat. It is designed to adopt Doppler principles, with ultralow and ultrasound output intensity and high sensitivity ultrasound transducer. The small handheld design and easy of use is intended for pregnant woman to do self-check at home, not for medical diagnostics. Specification: Ultrasound frequency: 2.0MHz in continual; Intensity: <10mW/cm2, Fetal Heart Rate measurement range: 50-120 bpm, Fetal Heart Rate measurement resolution: 1 bpm, Small volume 5.3(L)X3.7(W)X1.4(H) inch (135(L) 95(W) 35(H) mm), Weight: 0.4LB(180g) with battery Power supply: Two AA battery (included).