Fits 40mm gas masks. The item “8 Sealed Unissued Swiss 40mm NATO Gas Mask Respirator Filters” is in sale since Sunday, May 17, 2020. This item is in the category “Collectibles\Militaria\Surplus\Personal, Field Gear\Gas Masks”. The seller is “fullarmor610″ and is located in Shickshinny, Pennsylvania. This item can be shipped to United States.