Space-saving sleepers are a type of furniture that can be used for sleeping and seating. They are also known as cots (4 letters), which is an abbreviation for 'camping outdoor beds'. These beds are designed to be folded up and stored away when not in use, making them ideal for small spaces. They are usually made of lightweight materials such as canvas or metal, and are often used in camping, dorm rooms, and other areas where space is limited.