The Items tab on the Vault Settings dialog contains options for configuring units of measure, categories, lifecylce revisions, managing item properties, and defining custom numbering schemes. You can also disable the items feature.
Access the Items Tab on the Vault Settings Dialog
Administration
Vault Settings.

Enable or disable the Items feature to better control user access.
The units of measure are displayed in the Units of Measure dialog box. New units can also be defined.
Rules for bumping the revision can be specified as well as the default revision sequence to use. New revision sequences can also be defined. Automatic file locking can also be enforced on the Items tab.
The lifecycle state of an item can be indicated using a watermark on the associated visualization file. The watermark text, style, and position can be customized.
Disable Assignment of Design Files (Vault Professional 2012)
You can choose to disable the ability to assign item to design files such as .idw files. If this option is checked design files will only be linked to the Items for which they represent.