Abstract: A stiffening insert of shaped stiff material having openings parallel to the long axis of the material is disclosed. The openings present a serrated outline. The inserts may be applied to collars, cuffs, waist bands, clothes trim and other parts of apparel which need to be stiffened.

Abstract: A gas filter element comprising a holding frame and a plurality of self-supporting wedge-shaped filter pockets each having its wide end open and secured to said frame, each element comprising a pair of substantially symmetrical pocket halves secured to one another along the wedge edge and centrally along the opposite wedge end faces, and a plurality of laminar spacing elements with each pocket extending from adjacent the open end toward the wedge edge, each spacing element being secured to the opposite inclined wedge faces, each filter pocket being rendered self-supporting by the securing of the sub-elements to one another and the securing of the spacing elements to the pocket. Advantageously the filter pockets each comprises fusible fibers, the pocket halves being joined to one another by fusion and the spacing elements being secured to the pocket by fusion.