Or is it a contract.
All I can say for certain is that it is a 3 page legal document detailing all of the demands I have consented to by entering into a purchase agreement with International Business Machines for said nubs.
In fact, the document stipulates that should I disagree with any of the conditions, IBM would actually prefer not to sell me the nubs at all.
This is a lot of trouble to go through for six little pieces of rubber.
It is, though, very important rubber. I bought this laptop used, and the nub was all blackened on the top, and sort of torn up. Using it felt a little like wearing someone else's underwear, for two days in a row.
But after changing the rubber, I feel all pretty and clean again. This new nub rules. Now, to read the fine print...