Ultrasonic transducers as used in Silicon Chip projects such as the ultrasonic cleaner and boat antifouling. See website for data sheets. 50W 40kHz Ultrasonic Transducer Cat AU-5556 Specifications: • Static capacitance: 3000pF • Resonant frequency: 40kHz • Bandwidth: 3.9kHz • Impedance: 15 ohms • Insulated impedance: 1000Mohms • Power: 50W