This accessory will go with the 40" series 600 spiral tilt window balance. Product Code S600-40 that I will have to also order. The part in the picture is where the bottom tabs of the window go in to and then it slides in the track.
Paul from SWISCO responded:
October 5, 2017
Hello from SWISCO.com! Please compare the dimensions of your pivot shoe to our 15-046, which is very popular in vinyl windows.