The highly functional X-SOCKS RUN RETINA 4.0 are exactly what you need for your long-distance runs. The Retina Ultra-High Definition technology not only makes these socks lighter and more comfortable, but also allows them to be strategically combined with our other technologies. At the same time, the newly designed Lambertz-Nicholson Achilles tendon protector 4.0 protects the sensitive tendon area with dual cushioning against pressure, impact, and friction. For additional protection in the heel and ankle area, the AirFlow Ankle Pads provide support. Airconditioning Channel 4.0: 3D structures and special technical yarn improve air circulation, enhancing foot ventilation. Instep protector with Airvent Zone: The 3D knitting technique prevents the socks from sticking to the feet. The result is better ventilation and fewer blisters.