Model M4-1 Space Saver Keyboard with TrackPoint II
IBM M3/M4/ThinkPad buckling sleeves (Lexmark variant)
ABS with pad-printed legends
IBM black oval badge
Set 2/AT over PS/2
Designed for use with the IBM Netfinity Rack Keyboard Tray (P/N 28L4707)
More about this type of keyboard...
The IBM Space Saver Keyboard with TrackPoint II was a variant of the original Model M4 that featured an integrated TrackPoint II pointing stick. The Model M4-1 is notable for being the first IBM desktop keyboard to feature TrackPoint technology and the only Model M to retain a strain gauge-based pointing stick after Unicomp took over production.