The Rocketbook Core is a reusable smart notebook that allows users to write on its pages with a pen and then erasable with a special pen. It is perfect for taking notes during meetings or classes. The notebook has 32 pages of lined and ruled paper, measuring 8.5" x 11". It is compatible with the Rocketbook app, which allows users to save and organize their notes digitally. The notebook is suitable for personal or business use.