I dug this small Pockescope up a couple weeks ago and cant find one exactly like mine...It has pockescope- pat. applied for-wollensak rochester usa on it...Mine is 4"closed and 4 3/4" open 5/8" wide at both ends...
Here's a similar period advertisement, showing three different sizes and I would have to pick the middle sized one as having most similar shape to yours.
That model was 4 and a half times power as opposed to 6 times for the Senior and 3 times for the Junior.