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 Blue backlight lcd display for use conveniently at night 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¡à10% Ultrasonic intensity: ¡ü10mw/cm2 Comprehensive sensitivity: ¡ý90db Fhr range: 60--210bpm(¡à2bpm) Fhr alarm range: ¡ü100bpm or ¡ý160bpm Isptp: ¡ü0.1mpa Battery: 9v dry battery (optional for 8.4vni-mh rechargeable batteries and charger) Maximum audio output intensity: ¡ü1w Doppler frequency: 100--3000hz Static continuous working time: ¡ý2h Automatic dormancy time limit:1 minute Working temperature: 10-40¡æ Humidity: ¡ü80% Atmospheric pressure: 86--106kpa Packaging collocation: Single unit dimension: 24cm x 23cm x 12cm gross weight: 1.5kg 20 pcs/carton dimension: 44cm x 36cm x 42cm gross weight: 18kg Normative collocation: gallus, operation manual, approval certification, warranty card