This Pocket Fetal Doppler mainly applies to detect the fetal heartbeat rate from the twelfth week; LCD can display FHR, synchronous FHR signal, battery indicator, volume of sound and alarm indicator accurately; Built-in rechargeable battery can work continuously more than 5 hours; TFT LCD display for use conveniently at night; 4 modes count the FHR: Average, Auto, Manual and Instant Automatic power off (one minute), self-detect function, and alarm function when FHR is out of the normal range or battery power is in shortage; Only 270g, can be carried conveniently with a gallus; Built-in speaker and collocated with earphone jack; 2.0MHz probe. Specifications: Executive Standard: EN61266:1995 Ultrasonic frequency: 2.0MHz±10% Ultrasonic intensity: ?10mW/cm2 Comprehensive Sensitivity: ?90dB FHR range: 60--210bpm(±2bpm) FHR alarm range: ?100bpm or ?160bpm Isptp: ?0.1MPa Battery: 9V dry battery (optional for 8.4VNi-MH rechargeable battery and charger) Maximum audio output intensity: ?1W Doppler frequency: 100--3000Hz Static continuous working.