Press Information

MHI Thermal Systems Launches "Beaver Mask" to celebrate the 50th anniversary of Room Air conditioner
-- Facemasks made with the same allergen clear filter used in room air conditioners --


・ Four-layer structure filters 99% of virus droplets, bacteria, and pollen
・ Allergen clear filter technology inhibits the activity of captured viruses and pollen
・ Alongside plans to donate all proceeds to local Japanese municipalities

Tokyo, December 17, 2020 – From December 2020, Mitsubishi Heavy Industries Thermal Systems Ltd., part of Mitsubishi Heavy Industries (MHI) Group, will sell Beaver branded facemasks to the Japanese market. The facemasks branded as 'The Beaver Mask' are a single-use, general purpose (non-medical) mask that uses the same filter technology found in MHI Beaver Air Conditioners.

While typical masks only use a one-to-three layer structure, The Beaver Mask has a four-layer structure. The additional layers improve efficiencies in catching droplets from viruses, bacteria and pollen. Between layers, the mask integrates Japanese-made microfiber and allergen clear filters.
The filters between the outside and insider layers of the nonwoven fabric create a fine-mesh filter structure that have a 99% Bacterial Filtration Efficiency (BFE)(Note1) and Particle Filtration Efficiency (PFE)(Note2) rate. Laboratory testing also confirms that the mask also prevents virus and allergen reproduction and re-dispersion at a 99% inactivation rate. (Note3)

  • 1Bacterial Filtration Efficiency (BFE) is the proportion (%) of bacteria and other particles with a mean particle size of 4.0 to 5.0μm removed by the filter.
  • 2Particle Filtration Efficiency (PFE) s the proportion (%) of 0.1μm test particles (polystyrene latex sphere particles) removed by the filter.
  • 3This is the result of the virus inactivation test for the allergen clear filter (Testing laboratory: Kitasato Research Center for Environmental Science).

In celebration of the 50th anniversary of Beaver Air Conditioners, the masks will sell on in boxes of 30 pieces (3 pieces per bag x 10 bags).(Note) Currently not available.
The box, and masks, will feature an illustration of the popular beaver character from the Beaver Air Conditioners.

From the two million masks MHI Thermal Systems plans to produce and the company will donate masks free of charge to some nearby municipalities.

MHI Thermal Systems will continue to use its accumulated technology and expertise to contribute to society.

■Beaver Mask specifications (Box type: 3 pieces per bag x 10 bags)

Category Content
Article Name Mask (Beaver Mask)
Application Common cold, pollen, dust, etc.
Material Body/filter (polypropylene, rayon)
Ear straps (nylon, polyurethane)
Nose fitter (polyethylene)
Antibacterial Material Enzyme-based antibacterial agent
Processed portion: filter
Count 30 pieces (3 pieces x 10 bags)
Packaging Material Outer/inner packaging (polypropylene)
Sales Method Online sales through Currently not available.

Tags: air conditioner

About MHI Group

Mitsubishi Heavy Industries (MHI) Group is one of the world’s leading industrial groups, spanning energy, smart infrastructure, industrial machinery, aerospace and defense. MHI Group combines cutting-edge technology with deep experience to deliver innovative, integrated solutions that help to realize a carbon neutral world, improve the quality of life and ensure a safer world. For more information, please visit or follow our insights and stories on