This is a feature of Specialized road and MTB stems. An angled shim fits between the inside of the steerer clamp of the stem and the steerer tube of the fork. If you use the stem you got on your Specialized bike, you get four possible stem angles. And if you buy an aftermarket Specialized stem, you get 3 shims, yielding 12 possible angles.

Here's a link. http://www.specialized.com/us/en/bc/...jsp?spid=57223