Plastic caves in at the point of impact, leading to serious head injuries. Composite fiber dissipates impact across the shell saving the brain and its container. Composites have becom the 'gold' standard for performance at the highest level- be it F1, MotoGP, space tech or missiles. Apart from being able to withstand higher impact, composite fiber is also lighter than plastic, making it the obvious choice for pros and for Tiivra.