This is a vent I made to model Seaboard Airline ventilated boxcar. If you are a rabid SAL modeler this might not be for you. I had no real drawings and winged it.For the rest of us it is probably good enough. These are priced as each. 2 needed per car
More info is here
http://www.lanestrains.com/Seaboard_Express_Boxcar.htm