Duffle bags are multi-functional bags that are used for carrying various items, ranging from sports gear to travel essentials. They are also known as gym bags, backpacks, holdalls, travel bags, satchels, and duffel backpacks. Gym bags typically have a cylindrical shape and are made of durable materials such as nylon or polyester. Backpacks come in different sizes and shapes and often have multiple compartments for easy organization. Holdalls are larger than gym bags and are ideal for long journeys. Travel bags are generally larger and have wheels for smoother transportation. Satchels are smaller than duffle bags and often used for carrying books or laptops. Duffel backpacks combine the features of a backpack and a duffle bag.