Supports chimney pipe and provides a positive connection between support box and chimney with a built-in twistlock. Suitable for both flat and cathedral (A-Frame) ceiling applications. Also use in short attic spaces (see instructions). Fits between standard 12” on center joists and most manufactured home applications. Support Box includes Integrated Starter-Coupler, Integrated Flue Extension, and 2-piece Black Ceiling Trim. Integrated Flue Extension accepts either single-wall or double-wall stovepipe.