Octal aero helmet octal aero is based on the award winning octal helmet but has been developed further for aerodynamic performance and to be used in time trial and events where low drag is crucial without sacrificing safety weight or comfort it provides more coverage and additional protection of the temples and back of the head to further improve safety the eps liner is strategically thicker in most exposed areas and is covered by the outer pc shell the unique and fully wrapping unibody s