continuous sound. and the second one was for 13 minutes. again, a continuous sound. remember, ha"haixun 01" only hed it for 9 0 seconds or so. the fact that "old shield" heard it give them great optimism and that it's in the right place. they have refined the satellite handshake data. they now believe it puts it exactly where the "ocean shield" is. >> just to show our viewers, this is what they're looking for, one of the black boxes. light here is where the sounds would be coming from. you can see it's not very big. the other important thing is the pings were 37 kilohertz. why is that important? >> it's a particular frequency, 37.5 kilohertz is the frequency that those pingers transmit on.