I was wondering can anyone tell me the model of the first thunderbolt heard in this video? Last night the sirens here went off while i was at my cousins and they live 1/2 mile from a Thunderbolt that in the past has sounded like a dual tone but last night it sounded a bit single tone and almost exactly like the one first heard in the video. Thanks!
http://www.youtube.com/watch?v=u9KA-teD7xM