What fits and breathes like a thermal jersey but protects like a light jacket' Castelli's Nelmezzo RoS Jersey. It situates a layer of soft, insulating polyester against your skin or baselayer while a face of DWR-treated nylon adds wind and water resistance. During spring and fall, the Nelmezzo's protection is enough for most rides, and it transitions to winter as a baselayer beneath a shell. The jacket is finished with only-a-cyclist-understands features like a zip pull you can grip with thick gloves and a key pocket protected by a flap of weather-resistant material.