There two reasons for buying these stickers, one is because you have keyboard that does not light up and the other is a more practical solution to worn out keys, my last two computers have invisible A and L keys for some reason, and they are not that old either.
So these stickers will transform the worn out keyboard into one that looks cool and one that is illuminated too because these use the light from the monitor to become illuminated like the dial on an analogue watch.
These are the features and details of the handy keyboard stickers:
•High quality fluorescent print reflects any ambient source – no matter how small.
•Eases eye fatigue while typing in low-light levels.
•Matte surface that is pleasant to touch.
•Easy to apply – just peel and stick (yet allows for a clean full removal with no sticky residue).
•Can be trimmed to fit non-standard keyboards.
•Dimensions: (full sticker sheet) – 9.5″ x 4″
Priced at $9.99
Source [Think Geek]