Window Sash Balance

Hello, Bruce. Thanks for your photos. Based on what I see here, you have either our S380-27, S385-27, or S378-27 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.

Comparison of the S378, S380 and S385 balance shoes.

Great! If the shoe depth is 1", then Series 380 is going to be your best choice. 

To determine length, all you have to do is measure the metal channel. Don't include the plastic fittings in this measurement, ONLY the metal.

You can see detailed photos and measurements of each balance on their respective store pages, linked in my previous response.