The M39 Aerator Edit
The M39 Aerator/Aerotor is a Mask produced in Finland some time after World War 2. The mask itself is of poor quality, evidence of this ranges from cut marks around the edges of the mask, and, in some cases, failure of the Glue which holds the Inhale/Exhale Valve to the mask, likely due to both age and low quality. This mask bears many similarities to the Full-Head Finnish M39 Gas Mask from the WW2 Era, with the most obvious similarity being the completely identical Inhale/Exhale valve, as well as the Material and Color of rubber that makes up the mask. Not much is known about this mask, and it is quite an oddity.
The Thread Edit
The M39 Aerator uses a 40mm thread which seems to allow usage of 40mm GOST and NATO Filters. The filters that come with this mask, while no test information exists on them, will likely contain asbestos due to their age.
This mask is of a laughably low quality. The first issue, which is likely due to age, is that the glue holding this mask together has a habit of Failing, which allows the Inhale/Exhale system to come off of the mask. The Strap is simply an uncomfortable Rubber strap, which is quite tight on some masks, but loose on others, and non-adjustable. The Inhale-Exhale system is an unusual one, which uses a Spring-loaded Plastic plate instead of a Flutter Valve or other form of Conventional exhale system, which prevents a proper Air-tight seal. Along with this, the unusual shape and poor assembly of the mask prevent use of a "heavy" filter, as it will pull away from the wearer's face. The mask does not fit properly onto a person's face, due to design flaws, though the addition of a Second Strap would have prevented this issue, and, if one was to be desperate or interested enough in using this mask, could modify it to include a secondary strap. The poor-fitting nature causes exhaled air to blow up onto the Wearer's eyes, which may lead to irritation or dryness.