 streamers of some of that silver tinsel that you hang on the Christmas tree. You can tape that under the edge of the little vent area, and you can see it when they're blowing their air out of it. They don't move as much air as the electric ones, but they move the air for a longer period of time, and they don't consume any electricity at all, even though the electric ones don't use very much electricity. The other advantage to the solar ones that I think is real beneficial for us around here, too,