FlashGot is the free add-on for Firefox and Thunderbird, meant to handle single and massive ("all" and "selection") downloads with several external Download Managers.
FlashGot turns every supported download manager into a download manager for Firefox!
- for Windows (BitComet, Download Accelerator Plus, DownloadStudio FatRat, FlashGet, Free Download Manager, Fresh Download, GetRight, GigaGet, HiDownload, iGetter, InstantGet, Internet