The Oakley Pro Football Shield raises the standard on fit and clarity and is most compatible with the Riddell® Speedflex Helmet. Engineered with High Definition Optics® (HDO®), Prizm™ Technology, anti-fog performance, and PhysioMorphic™ Geometry, the Pro Shield is molded to fit the unique curvature of Speedflex helmets and facemasks while maintaining Oakley's standard of optical clarity.