A bum bag, also known as a fanny pack, is a small, lightweight bag worn around the waist. It typically features a strap that can be adjusted to fit securely, allowing the bag to sit comfortably on the hips or lower back. Bum bags are popular for their convenience, as they keep essentials like keys, wallets, and phones easily accessible while allowing for hands-free movement. Originally designed for outdoor activities, bum bags have evolved into a fashionable accessory. They come in various styles, colors, and materials, appealing to a wide range of users, from hikers to urban dwellers. Many brands, including Nike and Adidas, offer their own versions, making them a trendy choice for casual outings.