Plus, the box will be able to hold all your current sets.
From the post:
The Ultimate Mystic Vale Storage System, Expands Game to 6 Players & Adds More Expansion Content
As the struggle to restore the Valley of Life intensifies, the ranks of those combating the curse continues to swell. Druidic clans from across the land heed the call, including the Frostcaster and Nightvale clan.