To be easily tolerated by the climber, a climbing fall requires two factors: the resistance of all the elements of the safety chain (rope, carabiners, protection, etc.) and their ability to absorb part of the energy released in the fall. . The harness is practically static and transmits all the remaining energy in the thighs (which absorb it well), around the waist (which absorb quite well) and in the spine where all the microtraumas are added creating permanent effects. For this, Grivel has developed the GS composed of a semi-hard half shell to better distribute the forces, coupled inside with a special alveolar material capable of absorbing most of the energy without transferring it to the spine.