Not sure what this is. Seems like a clone or rebranding of IBM Model M keyboard
The key mechanism is buckling spring.
This seems to be used for IBM mainframes.
Affirmative Computer Products manufactures a complete line of keyboards to increase productivity for users moving from iSeries AS/400 Twinax (5250) and zSeries Mainframe Coax (3270) terminals that have 122-key keyboards to PCs or Thin Client / Ethernet Terminals.
[ from http://www.twindata.com/affirmative/5250keyboard.htm]