The Oakley SI Tombstone Prizm are specialized glasses optimized for competitive marksmen. XYZ optics maximize the field of view to include peripheries, and the Prizm lenses are engineered amplify contrast in order to make target identification much easier against a variety of backgrounds. Prizm lenses block certain color wavelengths to maximize contrast and reduce eye fatigue and are interchangeable for simple adaptation to different lighting situations. The single-release trigger on the stems allow for quick lens change and the rapid-release trigger keeps lenses clear of fingerprints. Each lens blocks UVA, UVB and blue light up to a 400 nanometers wavelength, and also features scratch-resistant and anti-fog coatings. The lightweight, O Matter frame is comfortable for long periods of use and is stress and impact resistant as well. This product is an advanced tool for any competitive shooter.