The Oakley Pro Football Shield raises the standard on fit and clarity and is most compatible with the Riddell(R) Speedflex Helmet. Engineered with High Definition Optics(R) (HDO(R)), Prizm(TM) Technology, anti-fog performance, and PhysioMorphic(TM) Geometry, the Pro Shield is molded to fit the unique curvature of Speedflex helmets and facemasks while maintaining Oakley's standard of optical clarity. Product Features High Definition Optics(R) (HDO(R)) for enhanced clarity Prizm(TM) lens technology improves visual detail Anti-fog performance maintains clear vision PhysioMorphic(TM) geometry for optimized fit Designed for Riddell(R) Speedflex helmet compatibility Molded shield shape for full coverage and protection