MailConverterTools PST Viewer is a tool used to view and open PST without Outlook. The software provides advanced filter options to find important emails by specifying criteria like To, From, Subject, etc. Apart from this,  the software has an export feature that allows users to save their selected PST files. It also includes all mailbox data such as emails, contacts, calendars, tasks, and more, and converts it into a new HTML file format.