NeatDownloadManager By J. Motallebi is the simplest, but the most useful download manager add-on for Firefox installed on a Mac OS so that it can help you download directly and instantly from any website, just by one click on an intended download link.
It works well and can use TOR network. Problems: it doesn't notify you which part of the temporary files fails to be merged in case of an error, don't work well with big files, don't have support or updates.
