Safe
A safe is a container that when you select it and select "Use Chest" it opens up a storage space that you can put items in. A safe has sixteen storage slots, each able to hold a stack of one type of item. Different stacks may be of the same or different items. Safes can only be accessed by the player who placed them and they can not be removed from their place by any other player.
Crafted
It is crafted at a Metalwork Bench with five (5) Iron Ingots.
Uses
They are used to hold items and store them without anyone else accessing the content.
Safes can be placed inside baskets or other chests. They continue to carry their contents, and can be stacked with chests that are empty or have differing contents. When a chest is later placed and used, its contents at the time of removal are available again. There is no way of identifying the contents of a chest before using it, so there is no guarantee that placing a chest from a stack will get you the chest you want.