WW2 U.S. leveler

About late 2008 I was able to purchase several of these levellers.
Normally not my line of interest, but because they were in such great condition I could not let them pass me.
I have opened one of the boxes to be able to shoot a picture.
All those I have are still packed and unopened.
Most have first a transparent layer of paper.
Underneath the paper is a layer of waxed paper to make it water resistant, along with a paper label.
On the label is the well know U.S. “bomb” symbol, that tells us that it is WW2 period, together with the specification description of the contents.
In the wax paper is a small carton box, that also has a white label with all most similar description as the one that is on the wax paper.
In the box is a pile of cotton that contains the brass leveller to protect it against sudden impacts.
Levellers are never used and are new old stock.
These levellers are used on anti-aircraft guns and other artillery pieces to make sure that they are positioned horizontal.
My guess is that they were use in a 3-some.

Markings: see pictures and description
Condition: mint