Concrete poles for telephone lines are made according to the technical specifications of Telefónica de España, S.A.U. and are endorsed by the corresponding Technical Approval Certificate. These poles comply with standard UNE-EN 12843 and bear the appropriate EC marking.      These poles comply with the standards UNE-EN 12843 and UNE 207016. They bear the appropriate EC marking. Concrete poles for power lines are listed as follows:      - Vibrated reinforced concrete (VC) poles      - Hollow vibrated reinforced concrete (HVC) poles              ADHORNA has the N seal of quality for these VC poles, being accepted by all the power companies operating in Spain (Iberdrola, Endesa, Unión Fenosa, Hidroeléctrica del Cantábrico and other small distributors). The differentiating features of this type of poles regarding the traditional VC vibrated reinforced concrete ones are their high torsional resistance and higher nominal forces.