HIGH TECH, CALF-HIGH. WE WILL NOT REST TILL YOU RUN MOST COMFORTABLY. The impact on the body during running is equal to many times your body weight. Bones, tendons and joints all feel the forces. The anatomically formed right/left footbed of the knee-high X-SOCKS® Running Mid Calf cushions and supports your foot effectively. The Achilles Tendon Protector keeps the edge of the shoe at a distance and therefore protects this sensitive tendon from friction and unpleasant chafing. The protector is constructed so the tendon is encased in its own recessed area. The patented AirConditioning Channel® under the sole of your foot provides for an active exchange of air with every step. This keeps the foot dry and therefore more resistant to blisters and chafing.