ZONTOM Defender Silicone Mask is first of its kind mask made from 100% Silicone Rubber for a long lasting usage. It comes with 360 days extra filters for a year long usage. It also describes how to make the filter at home once you exhaust with the extra filters given along with mask for 360 days.
This mask can also be sterilized daily in boiling water after removing the filter before every use. It is highly recommended for all occasion, all profession, all activities, all season.