Abstract: A stamped metal container for attachment to a structure in a fluid system as, for example, an air filter, for holding a body of fluid treating material in the system and having a bottom, a peripheral, upstanding side wall and an open top. A plurality of cutouts are located in the bottom and at least two of the cutouts are elongated and defined by tabs struck from the bottom at different locations thereon. Each tab has an end remaining attached to the container at or closely adjacent to the side wall. Each tab also has a length substantially greater than the height of the side wall and is directed upwardly and away from the bottom and substantially parallel to the side wall. The tabs may penetrate an air filter and be bent over to engage the backing thereof to hold the container thereon.