Product D1201-OW and D1201-DOW are "outside of wall" superior functionality dynamic fire dampers. They provide high quality performance as well as a small force drop like minded to many business programs. Special, inter-locking double pores and skin blade design eliminates combustible seals and offers flame safety below fireplace circumstances at https://heavy-duty-stainless-stee24455.blogsidea.com/43579799/fascination-about-heavy-duty-stainless-steel-damper-manufacturers