Online only -20% Clothing Nano Flex 3G Armwarmer Castelli 4519529 €35.96 €44.95 Choose Nano Flex for warmers that are great in dry conditions but also give some extra protection and warmth in wet conditions. We invented the category of water-protective thermal fabrics, and Castelli's proprietary Nano Flex is often imitated but never equaled. No compromises for any conditions. Shipping in 4/5 working days View