Features:  1. Advanced auto-correlation algorithm for high FHR accuracy 2. High sensitivity wide beam integrated sensor for reliable detection throughout pregnancy 3. Active noise reduction for crystal clear fetal heart sounds 4. Low ultrasound output dosage for ultimate safety 5. Advanced power management for long battery life 6. Elegant and compact design for easy home use  Description: Item type: Fetal monitoring   Size: App 125mm X 48mm X 32mm   Weight: App 80g(Including batteries)    Battery: 2 x AAA 1.5V Alkaline or 2 x AAA 1.2V NiCad   Auto Shut off: 1 min no signal     l Unit Controls    Buttons: On\/Off、 Volume   Frequency:  2.5MHz continuous wave   Acoustic output: Low power – exemption IEC61157 (Clause 6)    Headset: 100mW (32Ω stereo headset)   Audio response: 250Hz -1.25kHz    Display: 3 digit FHR   Range: 50-240 bpm   Accuracy: ±1% or ±1bpm whichever is greater   Resolution: 1 bpm   Classification: IEC60601-1、 type CF    Package Included:     1 X Host     1 X Battery      1 X Use manual     1 X Headset     1 X Coupling agent      Notes:       1. Please allow slight deviation for the measurement data and make sure you do not mind before ordering.       2. The real color of the item may be slightly different from the pictures shown on website           caused by many factors such as brightness of your monitor and light brightness.