The Nano Flex warmers have been in Castelli’s collection for seven year, and they’ve finally found a way to improve them. They have added an insert on the back in Nano Light fabric to help them bend around your knee better while keeping all the water protection. The Castelli Nano Flex+ Knee Warmer provides more comfort due to more flexibility, and is slightly more compact.
Nano Flex fabric
Water-resistant thermal and breathable
Nano Light insert on back for extra stretch, bringing better fit and comfort
Double-sided silicone grippers to keep the warmers in place