About the castelli nano flex arm warmer castelli advise that their nano flex warmers are great in dry conditions but also give some extra protection and warmth in wet conditions'. '.strtoupper('c')astelli invented the category of water protective thermal fabrics, and castellis proprietary nano flex is often imitated but never equalled'. '.strtoupper('n')o compromises for any conditions'. '.strtoupper('k')ey features water repellent thermal and breathable nano flex fabric and weigh only 66g for the pair flat lock stitching with single seam for improved comfort double sided silicone grippers to keep warmers in place about the brand castelli traces its roots back to a fine tailor vitore gianni in the heart of milan, founded in 1876'. '.strtoupper('t')hrough the years, vittore gianni clothed ac milan, juventus and the milan ballet'. '.strtoupper('t')he first cycling clothing was made in the 1910's for the world champion and five time giro champion alfredo binda'. '.strtoupper('c')astelli innovated the first aerodynamic lycra shorts in 1977 which were used in racing and for public sales'. '.strtoupper('c')astellis single minded mission is to make the most innovative clothing for the cyclists seeking maximum performance'. '.strtoupper('o')ver the past decade, castelli have led essentially every performance innovation in cycling clothing'. '.strtoupper('a')rm and leg warmers buying guide