Sleeping bags, also known as bedrolls, are a type of bedding used for camping and other outdoor activities. They are typically made from synthetic materials such as nylon or polyester and filled with insulation such as down or synthetic fibers. They are designed to keep the user warm and comfortable while sleeping outdoors. Sleeping bags come in a variety of shapes and sizes, and can be used alone or in combination with other bedding items such as blankets and pillows.