See the below image of a keyboard of an IBM ThinkPad X41. What is the font
used for labeling the keys?
Note that the font is used on many, if not all, ThinkPad keyboards. However, I
am not sure about that, and that’s the reason why I stayed specific to the X41
Image at full resolution: http://i.stack.imgur.com/z4kd4.png
Looks very much like Helvetica