Sensitivity:monitor 12 weeks above unborn fetal heart beat. Economic:Adopt with proffessional recharger battery,for effective costsaving and also can use 9.6V diaposable batteries. Practical:Unique network terminal service,can connect central network in hospital through dial-up at home,more timely,reliable and accurate for fetal monitoring. Ultrasound frequency:2.5+-0.25Mhz Ultrasound output power:10mW/cm DC power supply:9.6V rechargeable battery Working envirement temperature:10-40