Smith Optics Factor Tactical Sunglasses with Interchangeable Gray and Clear Lenses (Black Frame) Our Tactical Glasses meet US Military Spec MIL-PRF-31013,ANSI Z87.1 Change is inevitable. Tactics change, conditions change, light changes.The Factor Tactical and the Factor Max Tactical with PivLock technology will help you quickly adapt. Frames constructed of lightweight, impact resistant materials Lenses provide 100% protection from harmful UVA/UVB/UVC Megol nose pads and temples