the anna gasser signature model of the popular anon m4s. the anon m4s cylindrical goggle offers a precise fit with a wide field of vision and flat, cylindrical lenses. optimal for the combination of helmet and goggles. the reduced frame makes the m4s especially suitable for medium-sized and smaller face shapes.innovative magna-tech® technology allows for quick and easy lens changes through powerful magnets and offers unprecedented versatility.this version of the m4s comes with two cylindrical lenses with perceive optics for high-contrast clear vision in any terrain. high-quality anti-fog treatment ensures crystal-clear vision in all weather conditions. magnetic face mask integration (mfi®) offers seamless face mask attachment, while full-length vents provide consistent air circulation for clear, fog-free vision. perceive sun lensthe perceive sun bronze lenses are suitable for sunny and slightly cloudy days. perceive lenses give you high contrast to better see the terrain. transmittance of visible light: 6 %