More Information
Summary:A hollow structure for a face mask includes an inner wall, an outer wall spaced from the inner wall to define a hollow area between the inner wall and the outer wall, and a bottom wall that couples the inner wall to the outer wall. A first portion and a second portion together define a closable opening into the hollow area. The second portion is coupled to the outer wall by a bi-stable membrane that allows the second portion to move between (1) a first, opened position in which the second portion is spaced from the first portion to allow access to the hollow area through the opening, and (2) a second, closed position in which the second position abuts the first portion to close the opening.
Bibliography:Application Number: US201414505642