Since fly masks are often worn for many hours at a time, chafing can become a real problem. However, manufacturers have recognised this and are now doing a lot to prevent chafing. Today, fly masks are usually made of a very durable and tear-resistant, but also very light fabric. This reduces the risk of chafing.
Some styles are lined with fleece or have other padding in the areas that come into contact with the horse's skin. Some styles feature a strap that keeps the mesh of the mask away from the eyes and thus prevents irritation.