IBM Model M
Model M was the designation given by IBM to their buckling spring over membrane keyboard design. The Model M designation is most commonly associated with the 101/102-key IBM Enhanced Keyboard, it was also the designation for the IBM Wheelwriter keypad, IBM 122-key terminal keyboards, the IBM Space Saving Keyboard and certain variants. Various other buckling spring keyboards (and even a few rubber dome keyboards) received designations of Model M with some number following them. These are listed below.