Cyberduck is a free, open-source file transfer client that allows users to connect to various cloud storage services and servers. It supports protocols like FTP, SFTP, and WebDAV, making it versatile for transferring files between local and remote locations. Available for both Windows and macOS, Cyberduck features a user-friendly interface that simplifies file management. Users can easily upload, download, and synchronize files, as well as manage their cloud storage accounts, including popular services like Amazon S3 and Google Drive.