Life plus ultrasonic pocket fetal doppler is designed to meet routine examination requirement of obstetricians, mid wives and pregnant women. specifications. display : 60mm x 27mm lcd displayhart rate range :50210bpmresolution :lbpmaudio sampling frequency : 4khz 8khzsize: 30 (depth) x 85(width) x130 (height) mmaudio output power :0.5wauto shut off: 1 minuteweight: 250 g (including one battery)