Active Cooling Sleeveless Base Layer

##Castelli Active Cooling Sleeveless Base Layer Worn beneath your jersey, the Castelli Active Cooling Sleeveless Base Layer is a hot weather essential. The combination of fabrics helps retain some moisture against the skin, allows the air to flow freely and, in turn, brings an evaporative cooling effect to your core. It's best worn with a lightweight jersey and has a sleeveless, minimalist design.