The #4 covers can be filled with up to three inserts (they even come with one to get you started). Calendars, note pages, or sketchpads, the sky's the limit. Create inserts and slip them in and out according to whatever inspires you. The vegetable tanned leather will age beautifully over time, collecting marks and scars along the way, making it the perfect everyday companion to help you keep it all together. Plan your day, organize your mind, collect your thoughts.