Vintage United Sates Army Tank Periscope

This is the top section of a tank periscope, I believe based on the hand written letters and numbers inside the item that is from a WW2 to cold war era United States army tank , written inside is 'O.W.L/TD. 31914/2/5' it is heavy and solid with its mirrors in place, it measures nearly 4.5 inches wide and comes in good condition with some signs of wear and use.