CHX-2C++ Portable Fetal Doppler ( Two LED Display ) It's used for detecting the fetal heart rate(FHR) at hospital,clinic,family. ? Easy to use ? Two LED display FHR of real-time and average ? Built-in speaker ? Sound alarm function when FHR is out of the normal range ? Built-in rechargeable battery Specification: ? Ultrasonic Frequency: 2.5 MHz ? Dimension?185(L)* 190(W)* 130(H)mm ? Weight : 1.3kg ? Continuous work time: 8 hours Configuration: Rechargeable battery?Charger?Manual