Riders who enjoy a bit of crisp weather on the lower legs or don't like the feel of an ankle zipper will enjoy Castelli's Sorpasso RoS Knicker, which confidently braces against winter elements that would typically drive you to months on the indoor trainer. Designed for slightly warmer conditions that the Sorpoasso RoS Bib Tight, the Knicker still receives Castelli's familiar NanoFlex technology, now in its third generation, to boost water repellency while maintaining the breathability and warmth we've come to expect. As you're bent forward in the riding position, the anatomically mapped 3G paneling provides ample stretch to allow unrestricted movement at the knee and hip. Under heavy clouds and paceline wheel-spray, the Knicker sheds water with relative ease. Nano Flex Xtra Dry fabric is sewn to the upper bib, thighs, and the rear of the legs, so you'll stay dry and maintain body heat to maximize winter performance.The Sorpasso RoS uses Castelli's Progetto X2 Air seamless chamois, which is designed for peak comfort and performance during long winter base miles. Reflective panels are added to the rear, and the Knicker is rated for rides ranging from 50-61 degrees F.