Although the design seems simple, there is a lot more to the design than one would think. These breathable, warm, great fitting warmers uses a one pattern design that offers a tapered cut that follows the anatomy of the arm to offer a great fit. The Assos armWarmer_evo7 features light RX fabric that is thermal yet breathable for varying conditions. The upper portion of the armWarmer features a full circle of elastic to help them stay in place as you ride. The warmers are specific for the left and right arm so Assos added a small label to make sure you are wearing them correctly.