1,split-type design:seperate design between host and probe; 2,power with dry batteries AAA(1.5V*4); 1,split-type design:seperate design between host and probe;2,power with dry batteries AAA(1.5V*4);3,the probe taking the principle of fetal ultrasound to collect the fetal heartbeat signals of fetus; 4,can transmit the fetal heart signal to monitoring centre system with a headphone socket; 5, ...