Termius is a popular terminal emulator and SSH client that caters to system administrators and developers. It offers features such as the ability to manage multiple devices and connections, organize hosts into groups, and securely access remote servers from various platforms including Windows, macOS, Linux, iOS, and Android. The service provides a cross-platform sync feature to share settings and credentials between devices, and also supports SFTP for file transfers. A subscription typically includes advanced features like agent forwarding, terminal tabs, and easy setup for AWS EC2 instances.