FIB4178-CL / 4178-CL VISOR PROPIONATE CLEAR WIDE VIEW HIGH PERFORMANCE® Faceshield Windows HIGH PERFORMANCE® Faceshield Windows are injection molded from propionate, which is superior to other window materials in every significant performance characteristic. They're pre-formed to the exact curve of crown protectors for an exact fit and a perfect seal against dust, dirt and debris. Windows for virtually every jobsite hazard are .060" thick for an extra margin of protection. All products other than the steel mesh screens meet ANSI Z87+ Standard.