The 0800 Series is out there in two frame types to be used with steel duct: a double flange screw gap mounting style (M1) or perhaps a knock-over tab variety (M2). Equally models come with an easy set up cut-out template which makes the oval condition openings additional very easy https://aldersmokingchips67789.tusblogos.com/37196550/dampers-for-industrial-sector-for-dummies