Castelli Nano Flex 3G Knee Warmer Small BlackThe Nano Flex 3G is a Water-Repellent, Insulated, Lightweight kneewarmer. Each end of the warmers has double-sided silicone grippers that keep them in place while riding. The fabric used is Castelli’s Nano Flex, which is not only great for insulating but it is also a water-protective fabric.8055688938420