with cnn safety analyst david soucie and david gallo co-leader of the search for air france flight 447. and david soucie, how does this work? explain what you have here. >> a duquesne tester. inside we have -- that's the pinger. $750 unit. doesn't look very dramatic, does it? >> that would be in the so-called black box? >> yes. both in the cockpit voice recorder and the flight data recorder. there's two of them in here. every sea check on the aircraft, which is every 1,000 hours, this is removed and rebolted back in and replaced. the pinger includes the battery and signal transducer. inside of it if you look at this end, i don't know if you can get close enough to see that, but there's a plastic lip or plastic ring that separates the case which is the grounded area from