WARMTH THAT FITS UNDER A HELMET
Castelli's original Difesa cap is a Windstopper piece that's best for extreme conditions.
With the Difesa Thermal they removed the windproofing, but by doing so dramatically improved moisture management, so it's best for cool to cold conditions, especially with high-intensity riding. They placed a rib-knit wool wrap around the ears to keep you warm but keep it all relatively thin to fit under a helmet.
Weight: 52 g