These are used, Guaranteed to work as it should!!  They came from a working factory and were overstock.  The shroud looks like a thick industrial fabric of some sort.  I do not know how far these extend.  I took some measurements:

38.75 inches by 8.5 inches (at widest points) 

32 inches  by 7 inches

31.5 inches by 7.75 inches 

One of these is a Horizontal (LH) cover and the other a vertical

   

I don't know anything about industrial bellows, but I know these came out of a working environment -  I will try to answer your questions the best I can.....  Please ask for specific measurements.