Sonoline B Fetal Doppler in Blue with 3MHz Probe and Ultrasound Gel Gel is 2/3 full only used it few times, very good condition. Batteries not included The Sonoline B Pocket Fetal Doppler is a hand-held obstetrical unit, which can be used in hospital, clinic and home for listening to a baby's heartbeat. It contains components of an ultrasonic transducer and receiver, analog signal processing unit, Fetal Heart Rate (FHR) calculating unit, LCD display, Control Unit. The Sonoline B Pocket Fetal Doppler is a high performance model with (fetal heart rate) LCD digital display. It has 3 Operating Modes: Real-time FHR display mode, Average FHR display mode, and manual mode. It has a built-in speaker for audio output and is equipped with a earphone plug so one can listen privately. Main Features Battery status indicator Low power inspection of the battery Built-in speaker Output for headphones The probe can be changeable Probe inspection Backlight Auto shut off Support 2MHz,3MHz,4MHz,5MHz,8MHz probes Two pieces of AA 1.5V alkaline batteries Main performance Anti-electroshock Type: Internally powered equipment Anti-electroshock Degree: Type B applied part LCD Display: 45 mm × 25 mm FHR Measuring Range: 50 BPM ~ 240 BPM (BPM: beat per minute) Resolution: 1 BPM Accuracy: ± 2 BPM Power Consumption: < 0.8 W Voltage: DC 3.0 V Power Supply：TWO 1.5V（AA size）alkaline battery Suitable Using Range: Suitable for use after the 12th week of pregnancy Auto Shut-OFF: After 1 minute no signal, power off automatically