This is a set of 3 Kumon educational material binders. ★We can accommodate any combination of English, math, and Japanese if you purchase 3 binders. ★If you purchase without leaving a comment, we will send you 3 math binders. You can store Kumon worksheets in these binders. The thickness can be adjusted for 200 sheets or 400 sheets. When you start studying, it's difficult to keep all the vast amount of worksheets, but you don't want to throw them away... so you can file them by subject. Also, for children who have advanced to higher-level materials, their own completed worksheets become the best reference books. Filing them by subject is also a great way to remember old grammar when you get stuck. They fit exactly 200 or 400 sheets, without creating wasted space. They are easy to put on a bookshelf. 《Material》Paper Please take a look here ↓ #Kumon related, children's enjoyable collection If you have any questions, please feel free to comment.