Alside Sheffield Double Hung Window Double Coil Balance
Your shoe looks like a match for our 15-177. I am confident that this will replace your old one. Your balance coils look to be in good condition, too, so you can reuse them.
I agree that the 15-177 looks like the piece and that the coils are in good shape, but in your previous response to someone else you noted you had never seen a balance coil like ours. As you can see in the first picture the top plastic that holds a coil has broken off from the lower plastic piece. Do you also have this a "one piece plastic part" that holds the coils?
I'm not sure what response you saw, but I've seen your balance pretty much a dozen times a day for the past 10 years. It's very common.
The plastic cover isn't made anymore, but the manufacturer has a new way of doing it. You want to use the 15-144 cap, 15-143 bushing, and 15-145 barrel. These kind of "sandwich" over the spring, snapping in place and holding it steady in the track.
Thanks from Ohio..
All of these pieces are explicitly designed to work together, so they should fit. There isn't much to it: the 15-144 goes on one side and the 15-143 goes on the other. The 15-145 goes between them, on the post of the 15-143. They all sandwich together over the spring.
I know it's more complicated than the old cover, but the manufacturer no longer makes that piece. This is the style they've decided to go with in recent years.
No, you need to put these on every individual spring in the window. That's the same case for your original hardware, too. You need one cover per spring. If you have two springs, you need two covers.
Awesome! Glad to hear you got it sorted.