Koma-Mail is a simple, small email application and has a portable alternative version than that can be run standalone from a USB drive. KM allows you to send and receive emails from your POP3/IMAP accounts. It supports SSL (Secure Sockets Layer) and APOP (Authenticated Post Office Protocol) and contains options to block scripts, ActiveX and HTML (HyperText Markup Language) content for increased security.
Koma-Mail includes a spam filter with basic options and can be used with multiple accounts and multiple users. It can also import and export email messages and contacts by maintaining an encrypted database and additionally includes a simple RSS feed reader.