If there’s one failing of most warmers it’s that they absorb water like a sponge. On rainy days they end up waterlogged and providing compromised warmth. Nanoflex is a proprietary Castelli fabric. We begin with our super-warm and ultra-stretchy Thermoflex fabric, used in many of our winter garments, and then we coat the outside with ultra-tiny nanofilaments that cause raindrops to run off the fabric without soaking through. Despite its water-resistant finish, Nanoflex fabric remains highly breathable, keeping you comfortable in almost any conditions.
- Water-resistant Nanoflex fabric
- Same breathability , stretch, and warmth as our standard Thermoflex warmers
- Double-sided Silicone grippers keep the warmers in place
- Pack down small to stow away in your jersey pocket