Safety helmets are designed to protect the head from falling objects. The outer shell is made of polyethylene and the inner belt has a system of polyethylene bands or woven bands. Most headgear is designed with a hard plastic outer shell, foam padding or strap on the inside to keep the head away from the outer plastic. This inner belt / foam allows kinetic energy to be absorbed by impact. Helmets create an extra layer for the head to protect the user from some of the more serious forms of traumatic brain injury. The helmet aims to reduce the risk of serious head and brain injuries from severe impact or head injuries.