Largest one OEM for fetal monitor and CE fetal monitor transducer in china CE certification 1.0MHz ,9 crystal and PCB inside L8M-OEM CE test probe Ultrasound transducer:Transducer: Multi-crystals, pulsed doppler , high sensitively Strength: <5mW/cm2Working frequency: 1.0MHzToco:Measurement range: 0~100 unitsNon-linearity: < ±8%