You get two light weight 11 tooth three spoke carbon jockey wheels to replace your Shimano or Campy jockey wheels saving grams and looking fast. 
 
These are simple to self-install in your drivetrain (you take a 3mm allen key and unbolt the old jockey wheel, you install the new jockey wheel, and you do the bolt back up) - simple and you dont even need to remove the chain.  You will not find these in your local shop or on your friend's bike.  You will get asked about them - we do.   
 
We at Cyclespeed like these carbon wheels for several reasons.  Firstly you can do the mech plate up nice and tight and the wheels will still spin for about 4 seconds when you flick them, which means low friction in the drive train.  Try doing that with your current jockey wheels.  Secondly, they are light and stand out.  Customise your drive train now, installation is a 3mm allen key away. 
 
Prices are in Australian Dollars.