An apparatus, for non-destructively inspecting a sandwich panel defining an enclosed space, has an external and internal probe. The external probe is adjacent an external face-sheet of the sandwich panel and the internal probe is adjacent an internal face-sheet of the sandwich panel. The sandwich panel has a core material that is is interposed between the external and internal face-sheets of the sandwich panel. Each of the probes includes two elements that integrally form the probe. The external probe includes and is integrally formed from one of a magnetic field emitter and a magnetic field sensor, the magnetic field emitter emitting a magnetic field, and one of an ultrasonic transmit transducer and an ultrasonic receive transducer. The internal probe includes and is integrally formed from the other of the magnetic field emitter and the magnetic field sensor and the other of the ultrasonic transmit transducer and the ultrasonic receive transducer.