The 0800 Series is available in two body kinds to be used with steel duct: a double flange screw hole mounting form (M1) or a knock-more than tab kind (M2). Both equally models have a straightforward set up Slice-out template which makes the oval form openings further simple to Reduce. https://erickvmcrf.goabroadblog.com/36013054/everything-about-heavy-duty-stainless-steel-damper-manufacturers