HJC Squad Adult CS-MX 2 MX Motorcycle Helmet - MC-5F / X-Small ACS Advanced Channeling Ventilation System full front-to-back airflow flushes heat and humidity up and out the rear of the helmet Polycarbonate composite shell lightweight, superior fit and comfort using advanced CAD technology ACS Advanced Channeling Ventilation System full front-to-back airflow flushes heat and humidity up and out the rear of the helmet Plush removable and washable Nylex interior Large eye port with optimal visibility and superior goggle fit