I bought what they had at our local co-op, labeled for minis. (...after a judicious peek in the box.)
I'm relatively happy. The brand name is Farnam; I forget the "type/model" but it was in a pink box and has purple plushy fur. I like these masks because they fit Baby; she has a very small head. The "mask" material is fairly stiff, and the darts hold the mesh away from their eyes. On the days that I use the masks, I put masks on in the morning and remove at night. I really don't like putting anything on ours, but a couple years ago the flies were so bad that Coco and Baby got some nasty white eye goop.
I only use the masks when there's flies. This year I haven't had to use them much except a few days in May. These masks seem fairly sturdy. I bought 3 each for each horse. That way I can wash them. The only thing I guess I don't like is that the purple plushy stuff is a little hot; they get sweaty underneath. Also, Coco--our spooky mare--doesn't much like when I have to separate the Velcro to remove the mask. Oh well, sucks to be her. ;-}