... high sensitive transducer. Built-in 152mm long time thermal printer. Alarm System. More than 24 hours data storage which can be playback ... Frequency: 1MHz±5%Range: 30~210BPM,Ultrasonic Intensity: <5mW/cm2 Alarm Limit:Upper Limit: 160, 170, 180, 190bpmLower Limit: 90, 100 ...