The castelli pro mesh sleeveless base layer the pro cyclists we work with know the importance of the right base layer for the conditions the pro mesh is made for the widest range of conditions and is designed to keep you dry in cool to mild temperatures we39ll even put it under a flanders warm base layer in the coldest conditions we39ve given it a graphic print so you can show off that you have something special when you open your jersey zip castelli pro mesh sleeveles