The original Model M6 was the keyboard assembly for the IBM ThinkPad 700 and 720 series and IBM PS/55 Note C52 portable computers. Produced exclusively by Lexmark for IBM, the Model M6 was a relatively short-lived design as it was revised and superseded by the Model M6-1 not long after the ThinkPad 700 and PS/55 Note C52 were released. Technically speaking, they were an evolution of the Model M3/M4 buckling sleeves keyboard that further compacted the form factor and slightly altered the buckling sleeves switch to use a barrel-based slider actuator instead of a keycap-based rod actuator for registering keypresses when the key is pressed down.
