Like every GPA helmet, the 4S was developed with maximum protection as the focus. The 4S is a technological revolution with its 4 layers which enable optimum shock absorption as well as better resistance to lateral compression.
The outer shell, made of absorbent polymer, absorbs a first part of the shock by deforming.
The 2nd layer takes up the energy of the impact and absorbs it.
The 3rd shell, made of fibreglass, ensures the rigidity of the entire helmet to avert lateral compression.
The 4th layer is the polystyrene shell which completes the deceleration of the shock by crumpling under the impact, thus protecting the cranial vault from brain injuries.
An optimal ventilation system
Thanks to its numerous front and side vents and its rear outlets, this helmet provides maximum ventilation.
This new one-piece and removable liner can be washed and, if necessary, replaced. The soft and fluffy inner has been given an antibacterial treatment.
Better neck protection and increased hold
The classic chinstrap is replaced by a hybrid system, an exclusive from GPA. A cross between the twin lock system and the traditional chinstrap, its rear part is made of thermoplastic resin and incorporated fibreglass fabric. Its nylon straps, covered with synthetic leather, fasten by means of a two-part buckle. Thanks to its rigid part at the back which extends the shell, this hybrid chinstrap guarantees greater protection and better hold for the helmet on the head. Its more affordable price and design will also win over the more conventional riders as well.
Helmet shell 1: Sizes 53 – 56 cm
Helmet shell 2: Sizes 57 – 61 cm