The Castelli Men's Flanders Warm Long Sleeve Baselayer features a SottoZero fleece interior that insulates against low winter and spring temperatures while also wicking moisture and having an incredibly soft feel against the skin.

Mesh inserts at the underarms improve airflow, and the stretchy fit with flatlock seams means it layers perfectly underneath a jersey or jacket without hindering mobility or causing irritation. Flat hem construction lets it tuck securely into cycling bottoms without creeping up during the course of riding.