【Function】 BF-500++ Pocket Fetal Doppler can detect the fetal heart rate (FHR) as early as 12 weeks of pregnancy to the babys first moment of life and can be used in hospital, clinic, home etc. It also can display the FHR with blue backlight LCD and have memorable volume control, attached an earphone and a small bag. 【Technology】 Power：9.6V rechargeable batteries or 9V cells Ultrasonic frequency: 2.5 MHz ± 0.25 MHz Ultrasonic intensity: ≤5mW/C㎡ Work time: >6 H 【Unit】 net weight: 0.25kg gross weight: 0.6kg (including AC adapter) size: 200mm * 165mm * 65mm