Helmet

A helmet comprising:

• a first protective collapsible layer,
• a second protective collapsible layer, and
• at least one energy absorbing pad permeable to air arranged between said first and second protective collapsible layers, wherein each of the at least one energy absorbing pad comprises a plurality of cells connected to each other to form an array of energy absorbing cells,
• wherein the first protective collapsible layer and the second protective collapsible layer are coupled to each other;
• wherein at least one cavity is formed in a portion of an inner side of the first protective layer for accommodating said at least one energy absorbing pad, so that the at least one energy absorbing pad is entirely accommodated only in the corresponding at least one cavity of the first protective collapsible layer;
• wherein said first collapsible protective layer and said second protective collapsible layer are configured to fit each other;
• wherein the second protective collapsible layer is dome-shaped and an additional portion of the inner side of the first protective collapsible layer, outside the cavity is shaped to mate with the second protective collapsible layer;
• and
• wherein a low friction layer/coating is applied at a separation surface between the first protective collapsible layer and the second protective collapsible layer, such that the second protective collapsible layer rotates into the first protective collapsible layer like a ball-joint;
• and wherein one among the first protective collapsible layer and the second protective collapsible layer comprises one or more male elements configured to engage respective one or more female elements of the other one among the first protective collapsible layer and the second protective collapsible layer, whereby a mechanical coupling between the first protective collapsible layer and the second protective collapsible layer is realized by means of the male and female elements.