The range of 4S helmets is designed from 4 elements whose sandwich superimposition gives remarkable damping ability, as well as better resistance to lateral compression.
the outer shell, made of injected polymer, protects against contemptuous elements (which Could perforate the cap) and dampens a first part of the shock waves by deforming or breaking.
the 2nd layer of high intensity EVA foam will absorb and resorb some of the waves of shock, reducing the energy that will be transmitted to layers 3 and 4.
The 3rd layer is an injected polymer shell reinforced with fiberglass. This cap, more rigid than that of the 1st layer, reinforces the helmet in the event of crushing while absorbing a part of the energy and adds extra protection against the harsh elements.
The 4th layer is the expanded polystyrene (EPS) liner which completes the absorption and transmit shock waves by crashing under impact. It thus protects the cranial box from cephalic lesions.