It’s used for detecting the fetal heart rate(FHR) at hospital,clinic,family. Easy to use Built-in speaker Without LCD display Built-in rechargeable battery Specification: Ultrasonic Frequency: 2.5 MHz Dimension:185(L)x190(W)x130(H)mm Weight: 1.3kg Continuous work time: 8 hours Package:30.5x23.5x16cm/unit, 45x36x50cm/carton, 5units/carton,GW:9KG,NW:7.8KG