112 different combinations of books, there is always one for you 2Mushroom hole design, you can increase or decrease the number of core pages, move the inner page sort 3The unique hole design makes the inner page binding more tight and easy to carry 4The whole can be 360 degree folded, you can increase or decrease the number of pages at will. 5The mushroom button can be used for a long time, and the inner pages can be replaced continuously.
