Bike panniers are bags designed to attach to the sides of a bicycle, providing extra storage space for carrying items while riding. They are commonly used for commuting, touring, or grocery shopping, allowing cyclists to transport belongings without needing a backpack. Typically made from durable materials, bike panniers come in various sizes and styles to suit different needs. They can be mounted on a bicycle rack or directly onto the frame, and many feature waterproof designs to protect contents from the elements. Some panniers also include reflective elements for increased visibility during nighttime rides.