Unknown Viewfinder - Please help me identify

Recently I purchased a box filled with all sorts of camera parts and I am having trouble figuring out where they all belong. One item that has been bugging me for days is this rangefinder viewfinder. I have spent many hours online trying to figure out what camera this came from and now I have had it. It is really pissing me off.

I'm thinking someone on here might know.

The whole thing is about 2" wide and the viewfinder is 1 1/4" long