Smartshock Rotational Protective System Created for the modern mountain bike trail rider, the Altec Helmet perfectly balances low weight with superb ventilation and of course high levels of protection. At the heart of the Altec is the innovative Smartshock Rotational Protective System. A series of elastomers sits between the shell and liner. In the event of an impact, these compress and absorb energy to enhance head protection. Via independent movement and compression, they reduce energy transfer to the brain across a wide variety of speeds and impact types. This impact system works in unison with the Multi-Density EPS foam construction to give the very best protection available. Cool Comfort So head protection is first-rate. What about comfort? That's superb too. Inside the helmet, you'll find a moisture-wicking and anti-microbial liner working together to keep you dry and sweat-free even during the hottest of biking days. When the heat is on you'll also be happy to find the 15 large ventilation ports keep your head cool as fresh air rushes in. And with its Adjustable Ratcheting Fitment System, you'll get the fit just right via the simple twist of the rear dial. Pop your Altec on, twist. And go hit the trails.