The Military Surplus Israeli Gas Mask Filter is compatible with any gas mask with a NATO threaded connection. It is designed to circulate clean oxygen while preventing exposure to CBRN chemical, biological, radiological, and nuclear agents. Color may very. Features4.5" diameterType 80, 40mmSOLD AS COLLECTIBLEGrade 1: Excellent to New/Unissued - These Military Surplus Israeli Gas Mask Filters are 100% authentic and are rated in excellent to new/un-issued condition. Product may be outside of original manufacturer's packaging but they will show minimal or no signs of wear.Grade 2: Good to Very Good - These products show signs of light wear. Material may be lightly scratched and scuffs may be present but these items maintain 100% of their original functionality.Grade 3: Serviceable to Fair - Products show signs of heavy use. Products may have cracks or deep scratches but all imperfections will be less than 1/2" in size.