Supports chimney pipe and provides a positive connection between support box and chimney with a built-in twist-lock. 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. Supports up to 60' of DuraTech Chimney. Use adapter to attach DVL or DuraBlack to the support box. A 2” wide trim collar is included. Painted black.