gpa 4s speed air tls riding helmet black matt4S First Lady Riding Helmet Designed for optimal safety Built with 4 layers for successive impact absorption and enhanced resistance to lateral compression The 4S model is constructed as follows: the first layer is the outer shell, which absorbs the initial impact made from shock absorbing polymer, it is designed to deform upon impact. The second layer, the 2S, absorbs and dissipates the remaining impact energy. The third layer, the 3S, is the main