I've been using these UV/fly protection sheets for over ten years on my grey, now very white, three Welsh ponies. I live in Flagstaff, AZ, a mountain town at 7,000 ft. elevation. UV rays are a serious threat. The ponies are turned out together every day. These sheets are reasonably durable and will last at least one season, usually 2 seasons, sometimes three! The best thing about them is that I can mend them myself on my regular sewing machine. I think they are safer than the nylon mesh because if they get caught on something, they do tear. I liken them to a safety turn out halter.