Telefunken opus 6. What is special band

I just got this telefunken opus 6 for $140 everything works except for the special band I was wondering if anyone knows what that is used for. Radio is from 1955/1956. Has am/fm/SW/special

 

It’s a longwave band which is basically useless if you’re in N. America. You might hear what sounds like morse code from non directional beacons used for marine and aeronautical navigation.
Wiki has a list of longwave broadcasters.
https://en.m.wikipedia.org/wiki/List_of_longwave_radio_broadcasters

 

Good to know thanks for the help, look up special frequencies and couldn't find anything