A Sun hat is a hat which shades the face and shoulders from the sun. The sun can burn your head and shoulders so you can use the sun hat to protect your head and shoulders from harmful ultraviolet rays. Sun hats are common in places around the world, mainly in holiday resorts residing in countries close to the earths equator. Sun hats can range from small to large brims. Sun hats can be also certified to a seal that is physician endorsed and the brim is usually 4 to 7 inches and shades the face and shoulders and neck.