HC-SR04 Ultrasonic Sonar Distance Sensor + 2 x 10K resistors Adafruit Industries Go to product viewer dialog for this item.
Industrial-grade transducers are designed for high-power continuous or pulse operations, such as ultrasonic cleaning tanks or plastic welding machines. Ultrasonic Transducer 60W 40kHz Go to product viewer dialog for this item. buy ultrasonic transducer
A linear array probe used for vascular and musculoskeletal exams, also found at reLink Medical . Ultrasound HC-SR04 Ultrasonic Sonar Distance Sensor + 2 x