Brock foam is exclusive to Hyperlite by Bern Helmets. Brock is a light weight foam that allows moisture and air to circulate through it in any direction without the risk of absorption. Brock foam is also very resilient and returns to its shape after, impact, thus offering protection for multiple impact applications. Sink fit is a unique fit and feel featured in all Hyperlite b Bern helmets. This construction allows the helmet to ride at a low profile for a better fit and feel. Ear protection is an optional feature to all Hyperlite by Bern helmets. With a removable snap system, these soft conforming ear flaps offer maximum protection for high speed falls. Adjustable chin strap allows for a wide array of head shapes and sizes.