Jacob is designed to allow rescue operators a rapid and simple application on patients that have hypovolumetric shock. Spencer’s anti-shock trousers carry out a triple function for traumatised patients. The first consists of preventing haemostasis, by applying pressure to the surrounding tissue where there are bleeding blood vessels, thus reducing the blood flow. The second regards the self-transfusion of patients in a state of shock: the application of the trousers and the subsequent swelling of the internal air chambers immobilize the equivalent of the two units of blood from the extremity and from the abdomen, towards the heart, through the compression of the superficial draining vessels of the legs and pelvis. The third function entails the pneumatic immobilization of fractures of the lower limbs and pelvis and above all, of comminute or instable fractures. The valve, technological fulcrum of the Jacob is made with a precise and sensitive system constructed with stainless steel springs, kept in an aluminium body with polycarbonate inserts. The seals of the valve are made of silicon and Vyton, materials that guarantee an unalterable elasticity over time, even if attacked by atmospheric agents and organic or chemical liquids. A mixture of micro-components produced with care guarantee repeatability and reliability of the Jacob anti-shock trousers, the most widely sold air trauma pants in Europe.