Castelli Prosecco Tech Short Sleeve Base LayerCreated to slip under a thermal cycling jacket or jersey, the Castelli Prosecco Tech Short Sleeve Base Layer is all about balancing warmth with rapid sweat-wicking performance. It's ideally suited to when you're riding in the cooler weather of the transitional months of the year. The Prosecco Tech Short Sleeve Base Layer owes its impressive warmth and sweat-wicking performance to the combination of a proprietary stretch rib-knit polyester fabric and PrimaLoft® panels. Together they provide the perfect cool-weather heat regulation making this base layer ideal for anything from low-speed training miles to higher-intensity efforts.Castelli's Prosecco hydrophilic treatment offers optimal wicking ensuring you don't feel clammy while the lighter PrimaLoft® panels are deployed around the waist and back, just where your bib shorts/tights overlap, so you don't overheat there.  A crew-neck also makes it easy to wear with low-collar jerseys. Features:Materials: 100% PolyesterProprietary stretch rib-knit fabricProsecco hydrophilic treatment for maximum wickingPrimaLoft® panels at waist and back where bib tight covers upper bodyCrew neck closure to fit under short-collared jerseysSuggested temperature range: 10 to 20 degrees CBuy Castelli Clothing from Chain Reaction Cycles, the World's Largest Online Bike Store.