HJC C91 Solid HelmetHJC C91 Solid Helmet The HJC C91 delivers great features at a budget friendly price. Built with an Advanced Polycarbonate Composite Shell, its lightweight and designed for a superior fit and comfort using advanced CAD technology. The single lever chin bar is easy to operate, even with gloves. Inside, a drop down sun visor slides smoothly for quick light adjustments. A large top vent works with deep EPS channels to keep air flowing and your head cool.