Cooler bags are insulated containers designed to keep food and beverages cold for extended periods. They are commonly used for picnics, beach outings, camping trips, and tailgating events. Made from durable materials, cooler bags often feature a waterproof lining and a zippered closure to prevent leaks and maintain temperature. These bags come in various sizes and styles, from small lunch bags to large, wheeled coolers. Many cooler bags also include additional features like adjustable straps, pockets for utensils, and easy-to-clean surfaces. Popular brands include Igloo and Coleman, known for their quality and reliability in outdoor gear.