These work! After a few days of slightly breezy weather these things were covered in dead yellow flies (the scourge of north Florida in May and June). They greatly reduce the number of flying bugs and if you stand near them and make them sway, the yellow flies and horseflies will go for the ball and not you! However, just don't use a twig to make the ball move. I did that with one that I didn't really look at first and managed to poke a hole in it with surprisingly very little effort. Even deflated, though, the ball still does its job.