... Portable and light weight, easy to operate2. LCD data and wave display with backlight,3.Accurate FHR detection with clear sound4 ... the gel,gel weight is 150g)Probe: Detect principle: Ultrasonic wave Doppler Transducer frequency: 1.0MHz, 2.0 or 2. ... 35MPa Mode of operation: pulsed wave/continuous wave Effective shoot area:230mm2±10%( continuous wave) , 490mm2±10%( pulsed wave) FHR:FHR detect range: 50 ...