Gas mask 40mm NATO filter extension hose. For use with all 40mm NATO/STANAG masks/filters such as the ones sold above.  Installs between the filter and air intake of your mask.  New in original packaging of US manufacture, measures 30″ in overall length, both ends have an approximately 90 degree bend.  The male thread that goes into the mask has a swiveling adjustment capability, make sure the mask you intend to use it with has the clearance for this bend.  This hose will not properly fit the Soviet 40mm/GOST filters used with the masks sold below.  Other filters and accessories shown in some photos are not included, it is there to demonstrate possible usage.