Fly and summer sheets are a covering for horses that provides a barrier of protection against flies and other pesky insects, making them feel more comfortable. These sheets are typically made of open weave mesh, allowing for breathability in hot and buggy conditions. Some fly sheets are made with treated materials that provide additional protection against damaging UV rays that can fade the horse's hair and skin. Certain brands even feature mesh impregnated with insect repellent, enhancing the sheet's effectiveness in keeping insects away from the horse. When used during turnout, a fly sheet can improve a horse's experience by reducing stress, panic, and pacing, particularly in horses that are sensitive to insects.