Slightly off topic, but you are the guys to figure this out.. it came in a box of parts...

Its a gauge, nickel plated, about 1 inch wide, has a handle-slides into something. No way to connect it to anything-inductive, or set by hand only??

Reads E...F on a scale. Looks aircraft? Came in a cardboard tube thats well worn, might be a test gauge?

Help!!