An ultrasonic transducer device is pressed against the front surface of a structure, emits an ultrasonic pulse into the structure, and detects an echo profile from the structure. An indicator is activated if the echo profile includes a return pulse that at least is received from between the front surface and the back surface of the structure. An ultrasonic transducer device includes an ultrasonic transducer and a coupling element coupled to the transducer for disposition between the transducer and a surface of a structure. The coupling element serves as a delay line that allows time for quiescence in the transducer so that return pulses from shallow depths can be detected. The ultrasonic transducer is activated when multiple switches are pressed against a surface thus assuring both firm coupling and perpendicular disposition of the acoustic axis of the transducer relative to the surface.