Window channel balance

I'm not sure what you have, unfortunately. We have dozens of different balances with these stamps. They're not a product code or anything, they just indicates the strength of the spring.

In order to figure out what Series this is, I need you to remove an undamaged version of this balance from the window and show me clear pictures of the top and bottom nylon fittings. I will also need to know the dimensions of these fittings.

These photos are perfect, thanks! I appreciate it. 

Based on what I see here, you have either our S380-34, S385-34, or S378-34 depending on the depth of the bottom shoe. That's the only difference between them. I recommend measuring your shoe and referring to our dimensions to confirm the best match. I've shared a diagram below for your convenience.

One last important note: two balances in the same window should have the same stamp. Your original photo shows a 33-4 and a 33-3 stamp. If these are from different windows, then that's no big deal. But if they're in the same window then that means someone repaired this with the wrong parts at some point in the past. You're going to need to weigh your sash on a scale to verify which of those stamps is correct. We have a weight chart on all balance store pages to assist you to that end.

Comparison of the S378, S380 and S385 balance shoes.