Made from aluminium, it is very light and because it’s anodised also very durable. The benefit of such anodising is that foreign debris like grass and sand finds it more difficult to attach itself to the teeth meaning less maintenance and your belts will last longer too.
21t Side pulley use (03/21/2005)

A short while ago we introduced a 21t side pulley for the 710. It's meant as another tuning option for your car. There are a few different reasons and ways to use it.
First of all it stays clean longer. I for one raelly do not enjoy cleaning pulleys, and the coated alu doesn't seem to get dirty!
But more important are the handling changes.