The Solstice MIPS helmet is proof you don\\\'t have to spend a lot of money to get a great fitting, great looking and easy-to-use bike helmet. Featuring MIPS, Multi-directional Impact Protection System, it includes a sleek built-in brim with plug ports for a clean look when the additional visor is removed. MIPS (Multi-directional Impact Protection System) was developed by brain surgeons and scientists to help reduce rotational forces on the brain caused by angled impacts to the head. Key Features Designed for larger vents and increased airflow while maintaining structural integrity Built-in and removable visor options give you two choices for constant coverage The intuitive, one-handed Headmaster fit system adjusts height and circumference LockDown dividers make helmet strap management clean and easy to adjust Internal, recessed channels move airflow over your head to keep you cool and dry Soft, comfortable, moisture-wicking and washable helmet pads Trek Helmet Sizing GuideS/MM/LSize (head circumference)51-58cm55-61cm Helmets Buying Guide