I put a fly mask on Cali a couple of weeks ago because she tends to have "goopy" eyes and if I don't stay on top of her, attracts flies. Of course, her neighbors wanted one, too, and I was able to take these pics. Are fly masks the newest horse fashion? I bought these from Country Supply early in the summer when they were on sale. I bought 2 medium for the mustangs and the rest large. And, yes, for those who asked, horses can see through them. I held one up and it's like looking through a mesh...the holes are small enough to keep the flies out, but the horses can still see.