This is from a non-tilt window. It's 1/2" X 20". Markings on it are 19 4 KP CALDWELL.
Bob from SWISCO responded:
June 5, 2019
Thanks for posting. See either our S380-20 or S385-20. The only difference between these two balances is the 'depth' of the bottom nylon shoe, so compare both with your old hardware to see what matches best. You will need a stamp option of 1940.