No batteries or fancy invasive apps needed for this handmade leather 3x5 notebook. Perfect for walks in the woods when no screens are wanted. You can write your to-do lists, sketch ideas for anything, or start a fire in an emergency. What more can you ask for? Each notepad can be easily replaced once you use up the pages--the original uses a sustainable forest mix pad. Simply pick up a package of blank ones at the store.I use a clip so I don't loose my pen; it also helps the pages stay together. The notepad with clip and pen will fit in front or back pockets. You can order the leather to be dressed or not (light shoe shine with some beeswax mix) or let it it naturally build up a shine over time.