SharePoint Permission Batch Setting is useful for modifying all items permissions in a SharePoint list.
It is designed for this requirement. On one hand, SharePoint user has created unique permissions for items of a list. On the other hand, he needs to add or remove some permission to all the items. In this circumstance, modifying permissions to each item is hard for default SharePoint permission setting.
With SharePoint Permission Batch Setting, it is possible to add or remove permissions to users/groups or user/group field columns for all items. The user/group field column are columns which represent users/groups, including "Created By", "Modified By" etc. inner columns and other users/groups columns like, "Manager".