Permit to purchase 4 booster items.
Allows you to purchase the following booster items at shops:

Scroll of Wisdom, Scroll of Wisdom Ω,
Golden Amulet, Golden Amulet Ω

*These items can also be attained normally in-game.

*After installing DLC, start the game or load a save file from the Main Menu to access it.

More details on the official game page of Booster Item Set 2 ...