Hardshell Helmets This type of durable, traditional lid features an extra-hard outer shell, typically ABS plastic, that’s paired with a strap suspension system and a thin foam liner. Other terms for these helmets are suspension helmets and hybrid helmets. This type of helmet offers two primary advantages: Low price Long lifespan Shelled Foam Helmets This lightweight style features a thick layer of impact-absorbing polystyrene or polypropylene foam protected by a thin polycarbonate shell. Impact forces are dissipated via deformation.... (more)