What’s the fastest tool to batch convert DBX to PST?

I need to import lots of DBX files that were exported from Outlook Express into Outlook as PST files. I have several of these files. There are hundreds of emails, and it will take a long time to convert them all. Additionally, I would like to preserve the folder structure and attachments completely. Where can I find the most dependable and speedy software for converting DBX files to PST files in bulk without losing any data?