EXTRAORDINARY PROTECTION FOR EXTRAORDINARY DISTANCES. For real distance runners: The Run Evolution Sock. Double-layer technology reduces the constant risk of blisters with long distances. The inner sock layer absorbs friction because it doesn't slide against the skin, but rather against the outer sock layer. At the same time it transports moisture to the outer layer. In addition, the integrated Traverse AirFlow Channel System™ in combination with the AirConditioning Channel® helps maintain dry feet by pumping warm air out of the shoe. That's extremely important since damp skin is the one of the main causes of blisters. Look to the double-layer construction for doubled blister protection.