Window balances

Thanks for reaching out to us. Based on these photos, I recommend either the S380-12 or S385-12 depending on the depth of the bottom fitting. The stamp, however, doesn't match up to any of the listed options. You'll have to weigh the window sash on a scale and refer to the chart under the product description on the S380-12 and S385-12 store pages to determine the accordant stamp. 

Comparison of the S380 and S385 balance shoes.

Sure, we're happy to help. Before we go any further, can show us a photo of the inside of the metal channel where the innerspring connects to the pulley mechanism? That'd be located in the middle of the channel. I apologize for not asking that sooner. 

Thank you! We can help with this but it must be a custom order since your sash weight exceeds our options. For your replacements, we'll use the Series 385 with the 1160 stamp. A pair of balances with this stamp will support a sash weighing 15 to 18 pounds. Please allow us to confirm the availability of these balances and we will reach back out as soon as possible.

Okay so it looks like there's going to be a 5-6 week lead time. I'll go ahead and email you a purchase link for (2) S385-12 balances with the 1160 stamp that you can use to place an order on our website.

Please let us know if you have any questions.