HJC Helmets RPHA 10/RPS 10 Helmet (Black, X-Small) Max air-flow top vent; variable air flow is adjusted by glove-friendly dials on each intake vent Advanced P.I.M. (Premium Integrated Matrix) fiberglass; super lightweight shell is designed for superior fit and comfort using advanced CAD technology RapidFire shield replacement system; simple and secure shield ratchet system provides ultra-quick, tool-less removal and installation for efficient operation Optically-superior Pinlock-prepared 2D flat-racing shield; our innovative center one-touch open/close locking system is designed for an extremely secure seal Advanced Channeling Ventilation System; full front to back airflow flushes heat and humidity up and out