They actually came with the sled, part of some nice items that came stock with the Limited Edition M this year. So they are from Cat.
The mounting arms are aluminum, but the thing I don't like is they mount directly to the throttle block and brake block. So if you want to adjust them, you have to adjust the angle that these blocks sit on the handle bars.
It is a very clean looking way to mount them, but does not allow for much adjustment at all.
-John