are these vacuum tube shields?
 

this part and I have 2 more just like this one were found in an old shoe locker which was plumb full of antique radio parts.. I can identify everything except these.. are they electron tube shields? I see the holes on one end which might have been the holes for the pins of the tube and a larger hole in the side which could have been more chassis/wiring?..they also have what appears to be a thread to screw onto something?.. maybe they are not radio related at all but figured somebody here would know.. thanks in advance..