This is a used Finnish military M61 gas mask with a sealed 60mm filter.  The 60mm filter is the larger thread common on Canadian, Finnish and Serbian gas masks and will not fit masks with the more common 40mm NATO thread.  The Finnish Kaasunaamari M/61 was a licensed copy of the U.S. Army M9/M9A1 Field Protective Mask.

These masks are in very good condition but may have slight scuffs common with long term storage.  They have an adjustable six-point elastic band mounting head strap.

Extra 60mm filters are located in the gas mask filter section below.