Features of the Evolv Men's Rave Climbing Shoe Unlined leather provides maximum breathability and comfort TraxA(R) SAS provides the best friction plus maximum durablility Full-length Midsole and Outsole Variable Thickness Rand (VTR) system puts thinner rand rubber in Areas ot reduce pressure points and hot spots around the foot as well as thicker rubber for increased longevity in the High wear zones near the toe for durability and Performance