Brock USA has a proprietary multi-impact foam formulation using expanded polypropylene or polyethylene beads held together by an elastic adhesive that produces a closed-cell foam that is still porous. Brock Foam is made by fusing the round foam beads together just touching at their tangent points. The result is a resilient foam that allows moisture and air to pass through it. Depending on the size, roughness and pre-compression of the beads, they will compress under the force of a blow in various ways.
is a new technology that is engineered and tested to pass applicable standards including EN 1078 for biking, ASTM 2040 for snow sports, and CPSC for biking and skateboarding. Zipmold is a patent pending liquid foam injection process. When the liquid dries, a skin is formed on the surface providing a seamless, polished finish. Zipmold helmets have a higher weight to strength ratio than Inmold enabling Bern helmets to be lighter, thinner, and lower profile.
EPS Expanded PolyStyrene
is one of the most widespread foams used today. The EPS you see in a helmet is several quality grades above what is commonly used. It can be tuned to produce optimal crush for a given impact level by varying the density of the foam cells. Manufacturers can add internal reinforcing using nylon, carbon fiber or various types of plastics to reduce cracking as well, enabling the use of wider vents without compromising structural integrity.