Window Coil Balance
Thanks for reaching out! To confirm the right replacement coil balance assembly for your window, I'll need to see photos of the parts removed from the window channel. You'll also need to have the parts removed from the window to confirm the measurements for these parts.
I'll also need to know the stamp/marking on the metal coils to determine the correct spring strength needed for your window. if there are no stamps/markings, I'll need to know the exact weight of your window.
It appears that these could be the Series 161, however, they also look like they could be the 15-087 coil housing pivot along with the 15-086 tandem housing. I am leaning more towards the 15-087, given that your housing appears to have a plastic cam instead of a metal one like the Series 161 coil. The only way to confirm which of these is the correct series is to carefully compare the measurements for the housing of each part.
The coil housing pivot is compatible with the Series 180 coil balance spring. To determine which spring is needed for your housing, you'll need to look for any stamps/marking on the metal coil. If there are no stamps/markings or they cannot be read and/or cross-referenced, you'll need to obtain the exact weight of the sash. Then you'll take the sash weight and divide it by the total number of coils in the window.
For an idea on how to remove/install these balance assemblies, take a look at the video below from our Swisco YouTube channel. I hope this helps!