From ContentSmartz Email Sender Express Pro:
Mailing List Generator from Contentsmartz searches e-mail addresses directly from well known SMTP Servers. It auto detects the max e-mail verifying session for a single connection limited by current SMTP Server. And, it auto detects DNS server of user's local computer. Its multi-threading implementation allows up to 30 simultaneous e-mail search threads. The normal search speed can go up to 1500 e-mails per minute. It can export search results to plain text file. Professional user interface, very easy to use, can be set up in few minutes. Its easy to use graphical user interface makes it comprehensive to use.