can't reach the surface. it's 4400 meters at that point. depth of water. so they can't physically hear that signal from the surface. number three, we don't know what equipment the chinese is using. they say 37.5 kilohertz. but that's -- it could be a wide band frequency, it could be anywhere between 40 and 70 frequency kilohertz. so there are a lot of questions that have to be answered. i would discount that. >> so, art, let's play some sound now of what this pulse or the pinger would sound like. you were tacki intalking about single pulse is unusual, sounds like the wrong signal. here's an example of, i guess, what the correct signal would be, what the sound would be from that pinger. >> it's just a click. yeah. you got it. >> all right. so that's what it should sound like. we don't know if that's what the