Castelli Nano Flex+ Arm Warmer

A bright, brisk fall or spring day can turn drizzly in a flash and leave standard arm warmers damp, chilly, and certainly not doing their job to keep you warm. That is, unless you have a pair of Nano Flex Arm Warmers. Made from Castelli's proprietary, drizzle blocking Nanoflex fabric, these warmers keep you comfy even when the weather goes south. Nano Flex starts its life as Castelli's super warm and ultra stretchy Thermoflex fabric, used in many of its winter pieces, and then gains and outer coating of tiny nanofilaments of silicone fiber. These fibers create a near waterproof barrier to moisture, and raindrops run off the fabric without soaking through. Despite its water resistant finish, Nano Flex fabric remains highly breathable, keeping you comfortable in almost any conditions. Across the back, Castelli utilizes a panel of its lighter Nano Light fabric to increase stretchiness around your elbow for full freedom of motion and comfort no matter how many miles are on the schedule.