This aluminum frame extrusion is used to make the sash (front frame) on a Hehr Hall-Mark 12 window. This profile is used to make the bottoms and sides of the frame. A different profile VTS-2143B is used as the top section of the frame. You will need to miter and weld corners.
Comes 47" long so you will likely need more than one of these to make a single sash.
Used on Airstreams from 1961 to 1965.
Mill finish can be polished.