Sylpheed is a simple, lightweight but featureful, and easy-to-use e-mail client (mailer, MUA). Simple, beautiful, and well-polished user interface. Comfortable operationality which is built in detail. Well-organized, easy-to-understand configuration. Lightweight operation. High reliability. Internationalization and Multilingualization support. High-level Japanese processing. Various protocols support. Security features (GnuPG, SSL/TLSv1). Powerful filtering and search. Junk mail control. Flexible cooperation with external commands