The B2 Compute starts with the 2� Center Section, which is designed to hold 13� laptops. Add a Front and Rear End Cap and you have an extraordinary laptop bag. The Front End Cap allows you to store items such as power cords, backup drives, flash drives, cameras, smart phones, tools, keys, etc. Meanwhile, the Rear End Cap allows you to store your folders and documents. This can be used daily or you can attach the 2� Center Section to Front and Rear Bags when traveling.