The portable deposit box was a fate cards reward from the Sizzling Summer promotional event. This item allows the player to place a portable bank deposit box almost anywhere in the game and will last for 1 hour. All unused portable deposit boxes from the original promotion were removed from the game on 1 January 2013 with the update Happy New Year!.
During the September 2014, 2015, 2017, 2018, and 2019 Balthazar's Big Raffle event, portable deposit boxes could be won by entering the raffles on Tuesdays (2017, 2018, 2019), Thursdays (2015), or Fridays (2014).
For an exhaustive list of all known sources for this item, see here
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