Valved masks are a type of semi-disposable dust mask used to help keep dust and debris out of the mouth and nose.

Valved masks do not provide any protection from airborne chemicals and solvents - so don't use them for painting, instead buy a respirator. Valved masks help keep contaminants like sawdust, metal filings, dust from rust, etc out of the mouth and nose.

The valve or valves - which are usually located either in the center of the mask, or with one in either side of the mask - are designed to help vent air faster during exhalation. This has the effect of reducing the humidity inside the mask.