Ultrasonic Digital Doppler Operating Probe Frequency 2 MHZ for obstetric & Gynecological applications. Facility for earphone. Operated on mains as well as with rechargeable battery, Three Digit L.E.D. display to give readout or rate of Heart beats per minute. Two digit L.E.D. display to give readout of volume. High and Low alarm indication. Beat hold facility is alsoprovided. Individual Fetal & Adult mode of operation.