Doing gravel sometimes means slightly lower speeds at a higher level of effort, so breathability becomes even more important and you can dress a little lighter. The Castelli Unlimited Thermal long-sleeved shirt is characterized by a brushed fabric that offers a high level of insulation by letting the right amount of air pass through for ventilation, without causing a cooling. The functionality of this garment is also given by the three rear pockets and silicone inserts while the YKK Vislon zipper is the smoothest zip we've ever found and allows quick adjustment when the temperature changes.