ALEXANDRIA, Va., Jan. 13 -- United States Patent no. 12,521,581, issued on Jan. 13.
"Protection device for the respiratory tract" was invented by Silvio Marino (Aulla, Italy).
According to the abstract* released by the U.S. Patent & Trademark Office: "Protection device of the respiratory tract of a person including a mask body of any convenient rigid or semi-rigid material suitable to cover the mouth and nose of a person, at least one pair of housings, placed on the sides of the mask body designed to hold a sleeve inside each of them, a spring inserted inside each sleeve, whose first end is fixed to the lower edge of the sleeve while the second end has a fixing arrangement which allow the two springs to join together behind the head of th...