Perfect for ambitious mountain bikers, the Giro Phase helmet is comfortable & highly practical due to a myriad of technology designed to keep you safe mile after mile. Thanks to an Acu Dial 2 system you can dial in the perfect fit in seconds, & with a highly durable in-mold EPS liner construction, the Giro Phase Helmet means that you can tackle daunting climbs & rock strewn single tracks with complete confidence.