This option will display all the locked accounts in the domain, additional details are also display for the accounts, including when the user's password was lasted changed, locked out time and last bad password time.
The details returned are the value of the attributes stored on the specified server, as some attributes are not replicated between Domain Controller, and are the local values on the specified server, and may not represent the most up to date value. To retrieve the most up value from all the Domain Controllers you should use the Last Logon option, which a linked option from the right click context menu which will automatically display the details for the selected item. See Last Logon
The unlock button can be used to unlock the selected accounts, this can be a single or multiple accounts.