M40 M42 US Military Protective Mask Size Medium Army Marines Gas Mask ProMask. Fully functional M40/M42 ProMask in size Medium. Attached is a 3M filter. The included filter is for training and riot agent (CS/CN) protection purposes only.This filter will not stop CBRN threats! Lens may have small scratches, this is a used mask. Does not include bag, hood, second skin, lens covers, or booklet. The item "M40 M42 US Military Protective Mask Size Medium Army Marines Gas Mask ProMask" is in sale since Saturday, February 8, 2020. This item is in the category "Collectibles\Militaria\Surplus\Personal, Field Gear\Other Surplus Military Gear". The seller is "therealsydesho" and is located in Middletown, Pennsylvania. This item can be shipped to United States.