Insert for the sequence junior game the main box is designed with the width of 259mm and fits snugly.

I have used the holders which can be printet from here: [https://makerworld.com/en/models/652375-sequence-for-kids-chip-holder#profileId-579153](https://makerworld.com/en/models/652375-sequence-for-kids-chip-holder#profileId-579153)