What was one of the distinctive features of the M-209 device?

The M-209 device was notably designed to be portable, which allowed for ease of use by military personnel in various environments. This portability was one of its key features, as it needed to be lightweight and compact enough for field operations where mobility was essential. The M-209 served as a mechanical cipher machine used during World War II to encrypt and decrypt messages, enabling secure communication. Its design prioritized carrying convenience, making it suitable for the rapid and dynamic nature of military operations at that time.