Model 1290F is a cheap legitimate round fire damper made and capable for position-of-origin hearth containment the place spherical ductwork passes as a result of metal stud drywall partitions or masonry walls that have a hearth resistance ranking of approximately two hrs and creating codes demand a fireplace damper. Options https://martinrjxln.bcbloggers.com/36102855/heavy-duty-stainless-steel-damper-manufacturers-an-overview