The Castelli Thermoflex 2 arm warmers offer luxuriously fleecy warmth on the coolest rides. If you don't need the extra wet weather protection of Nano Flex, or if you've always been happy with traditional warmers, you'll find that Castelli's Thermoflex warmers offer the softest, most luxurious fabric combined with careful attention to construction details.Thermoflex is luxuriously warm and stretchy in dry conditions but is not intended for wet conditions.Key Features:Thermoflex 2 fabric for exceptional warmth and softnessMinimal seam construction for aesthetic versatility and freedom of movementEasily packable into a pocketHighly breathable but also insulatingOptimal temperature range is 8°c20°c