Jalema expanding files are great for files that may grow to large sizes. The adjustable spine allows for expansion of up to 3" of documents in each file. An installed JalemaClip helps to secure the pages. Furthermore, there is an elastic band on the cover that loops over the back corners to keep the cover closed and protect the contents of the file. Choose an expanding file with 3 flaps to create a "box" around your documents for added protection.