.WAB File Extension
What is a WAB file?
Address book file that contains contact information, such as names and e-mail addresses; used by Microsoft Outlook Express, a popular free email program; similar to the .PAB file used by the full version of Microsoft Outlook.
WAB files can be copied and used to backup and restore Outlook Express contact data. They can also be used to import contacts into Outlook.
NOTE: The Stellar DBX to PST Converter program can be used to convert Outlook Express WAB files to the Outlook .PST format. You can then save converted files to PDF, HTML, Office 365, and RTF formats.