In rainy conditions, kneewarmers suffer from most of the same problems that legwarmers suffer. The fabric absorbs some water and their ability to keep your joints warm becomes compromised. The Castelli Nanoflex Kneewarmers solve the issues that challenge kneewarmers caused when riding in cold and wet conditions.

Nanoflex is a proprietary Castelli fabric. The mill begins with Castelli's super-warm and ultra-stretchy Thermoflex fabric, used in many of its winter garments and then coats the outside with ultra-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, Nanoflex fabric remains highly breathable, keeping you comfortable in almost any conditions.

Silicone leg grippers keep the Nanoflex Kneewarmers in place even on the hardest rides. They run longer than some we've seen, from mid-thigh to the bottom of the calf. Reflective logos are printed at the knee and on the side of the calf to help you be seen on the road.