Waterproof Ultrasonic Sensor with Separate Probe

Most ultrasonic distance sensors aren't waterproof which can be a problem if you need your project to withstand the elements outdoors. No need to worry any more!
This is a waterproof & ultrasonic distance sensor with a waterproof sealed emitter,  suitable for outdoor applications such as car reversing sensors, security alarms, industrial inspection, etc. What will you make?