Coil Balancer
Thanks for reaching out! Your pivot shoe resembles our coil balance shoe, part 15-180. Look over the dimensions and compare them to your original coil balance shoes to confirm that this is the right fit. I am confident these are the right fit.
These shoes are compatible with the Series 190 Coil Balance Spring. If there are no stamps that will help you determine the spring spring you need for the window, you'll need to obtain the exact weight of your window. Once you have the window weight, you'll divide the weight by the number of coils in the window to determine the spring strength needed.
Take a look at these parts and the other linked items to see what you think.