A spinnaker is a type of sail used on sailing boats, designed to catch the wind when sailing downwind. It is typically larger and more balloon-like than other sails, allowing for increased speed and stability. Spinnakers are usually made from lightweight materials to maximize their efficiency and are often brightly colored for visibility. There are two main types of spinnakers: the symmetrical spinnaker, which has a balanced shape and is used for reaching, and the asymmetrical spinnaker, which is more streamlined and better suited for broad reaching. Sailors use spinnakers to enhance performance during races and long-distance sailing.