The colour has been chosen to interchange with both colourways of the 1.11 short and 1.21 jerseys. The material is Castelli's Thermoflex fabric, a step up from the Roubaix fabric that most companies use.
It has a slightly tighter knit with higher loft fleece that happens to be more stretchy. This is useful for cyclists, as we often have to make contortionist moves when searching around to get into our jerseys rear pockets. Or lift a coffee to our mouth. Or reach down to pull our socks up.