Top-end technology and features for those seeking the best. Smiths VaporFit system provides easy and effective size adjustment; MIPS reduces the rotational effects of an oblique impact to the head. Hybrid construction combines the best of a tough hard shell with lightweight in-mould. Aerocore uses Koroyd for impressive air circulation and exceptional energy absorbing properties. Active venting allows airflow to be controlled.SmallMedium51-55cm55-59cm