These socks are designed in Switzerland and made in Italy and are full of details that serve runners. X-Bionic products have hundreds of test victories and more than 800 different technical solutions have been patented in connection with them. As you can tell from the "4.0" in the name, this is the fourth development version of this model of running socks. - Lambertz-Nicholson Achilles tendon protector - Ventilation channel: 3D structure and technical material enable air exchange - "Suppronation bandage" supports the healthy position of the foot and reduces the strain on the ankle - 70% polyamide, 16% polypropylene, 4% elastane, 1% polyester - Protection of the inner edge of the foot with "AirVent Zone" that improves ventilation