balance

Thanks for reaching out! The black piece attached to the bottom of the balance support appears to be a bumper, which looks similar to part 15-148 . This is typically compatible with coil balance supports like parts 15-150S and 15-150D , however, I am unable to tell if yours is a single or double coil support.

These parts are typically compatible with either the 15-111 or 15-191 coil balance shoe. The difference between the two shoes is that the 15-191 is a heavy duty version. If the shoes does not match what you have, I'll need to see a photo of your existing pivot shoe.

Alternate image for 15-111

The coil balance springs compatible with these shoes and supports are the Series 160 springs. To determine which spring(s) you'll need. Take a look at the stamps on the coils to determine the spring strength needed. If there are no stamps, you'll need to take the exact weight of the window and divide it by the total number of coils in the window.

Let me know if you have any questions.