If any users want to import Outlook calendar from OST to ICS with the use of the best tool? Then I recommend using the very powerful software- The eSoftTools OST to PST Converter Software. This tool is completely amazing and different from the other tool. It gives a free demo version for every new user. Users can use this feature and convert up to 25 files without investing any money. The software provides the filter option. Users can use this filter option and convert only selected files.