Your Safety Deposit Box keeps your items safe from the Pant Devil and other random events which may steal the items in your inventory.
There are two ways to search for items in your SDB. The first is by entering a search term. This doesn't have to be the exct item name. Typing code will bring up all your codestones, plus an item such as "Code Symbol Dice Set". The other way to search is to select a category. Selecting "codestones" will only bring up your codestones, and not other items, such as codestone plushies, or "Code Symbol Dice Set". You can also combine these two search features if you would prefer.
Note: This concept is based on the boxes that real banks have in their safes called safe deposit boxes.
There is currently only 1 item associated with the safety deposit box; "Safety Deposit Box (TCG)"