Can you identify this keyboard

[raheemlo]

My buddy picked this up at a local yardsale in the free pile.

• Cherry MX compatible stems
  
  Rubber membrane
  
  UNIX/HHKB alpha layout
  
  No ESC key
  
  No 0 or decimal on numpad
  
  The longest space bar I have ever seen
  
  PS2
  How a Text to Speech Tool Works For Educators?
  Made in Germany

Makes me think of a BTC slider over membrane but otherwise I have no idea.

Any help would be appreciated!

For pictures, see link below

https://imgur.com/gallery/spaqR5c

[Noobmaen]

It is some kind of preh dome with slider keyboard, I have the same model. Extremely tactile domes in my experience