A fly rug or fly sheet is a piece of horse clothing designed to protect horses from flies, mosquitoes, and other insects during the summer months. It typically covers the horse's body from the neck to the tail, with straps or fastenings to secure it in place. Fly rugs are usually made of lightweight, breathable fabrics that allow air to circulate and prevent the horse from overheating. They may also feature UV protection to shield the horse's skin from the sun's harmful rays. Fly rugs are a popular choice for horse owners who want to keep their horses comfortable and healthy during the warmer months.