Smith Optics Aegis Eye Shield with Clear Installed and Gray/Yellow Spare Lens Aegis Eyeshield Glasses meet US Military Spec MIL-PRF-31013,ANSI Z871.1-2003 and EN 166 standards Tapered Lens Technology for distortion free optics-All Aegis Eyeshield glasses are compatible with the Smith Elite Interchangeable Rx System PivLock Lens Interchange Technology allows for fast lens exchange Lenses provide 100% protection from harmful UVA/UVB/UVC rays-Anti-fog and scratch resistant on all lenses Megol temples and soft nose to hold eyeshield in place