Editing IBM buckling rubber sleeve (section)

==Models M6 & M6-1==
[[File:M6 components.jpg|thumb|right|M6/M6-1 type switch components]]
The second implementation of IBM's buckling rubber sleeve was introduced as the Model M6 in October 1992 with the IBM ThinkPad 700 series. A minor update to the design, Model M6-1, was introduced in September 1993 with the IBM ThinkPad 750 series. The principal difference between the original type and this one is the change from rod actuation to barrel slider actuation. The keycaps now have a crosspoint mount, with a brown-coloured minimalistic slider (M6) or black-coloured 'filled-out' slider (M6-1) actuating the membrane. Despite this change, the sleeves themselves remain identical. M6 and M6-1 also saw much wider adoption, becoming the primary ThinkPad keyboard switch until and including the IBM RS/6000 Notebook 860 introduced in November 1996. M6 seems to have been exclusively produced by Lexmark, however, for M6-1, production was transferred to Key Tronic sometime between Q4 1995 and Q2 1996. M6s and M6-1s were also produced for a several companies unrelated to IBM or Lexmark including AST, CompuAdd, Cube Computers and Tadpole<ref name="sharkm3m6article" />, and an M6-1 based design was even employed for the Apple Newton MessagePad Keyboard model X0044<ref name="sharkX0044article" />. The last year observed to have an M6-1 example produced within is 1999<ref name="mklatem61example" />.