The A-TAC is designed to meet rigid standards of the NFPA 1971 standards. Hard-coated outer lens with a superior anti-fog inner surface is designed to meet the needs of the specific environment. Paulson A-TAC goggles fit over prescription, safety and sun protective spectacles. Paulson manufactures the A-SGK aluminum goggle keeper, included with this goggle, that places the goggle at the best possible position for ergonomic wear and will not damage the helmet brim.