Abstract: A press-on retainer is configured to retain a fire-stop sleeve in an opening. The retainer includes a body formed of sheet metal. The body is configured to define a concave shape, a hole in the body, and a plurality of segments extending radially from the hole. Each segment is includes an angled portion at the end of the segment that defines the hole with a diameter suitable to accept the sleeve. The angled portions are configured to allow the retainer to be pressed onto the sleeve in a first direction, and thereafter prevent the retainer from being moved in a second direction opposite the first direction.