The dungeon cards model is designed to be an insert for the cobranded Munchkin games released through USAopoly that involve dungeon (double-sized) cards and markers.  Munchkin: Scooby-Doo! is an example.

The small cards model is designed to be an insert for the games with no dungeon (double-sized) cards.  There is still a tray for dice and markers.  

Sized to fit on a print bed of 220mm with cutouts to make it easier to pick up cards.