Hero Realms Adventure Storage Box - Rules of Play says:

This box will hold your entire Hero Realms collection, with or without sleeves, with room to spare for future sets and even a playmat! Use the included foam blocks to hold your cards firmly in place. The high-quality plastic dividers included will allow you to separate your cards by set, and/or have a deck ready to play with dividers for Market Deck, Fire Gems, Personal Decks, and Score Cards.