18" 1710 cs bm
Hi there!
What you have here is called an extended travel balance. It isn't a part of our stock catalog but we can still help via custom order. However, the metal channel should measure 17-7/8" long. Can you double-check and confirm that for us? We'd also like to see a close-up photo of the metal hook attached to the end of the pulley cord. Additionally, how many balances are you looking to order?
Thank you! Our minimum for custom orders is 2 but we always recommend replacing balances in pairs. Pairing an old balance with a new one would only cause the new hardware to wear out much faster.
With that said, I will email you a purchase link and price quote for (2) balances that you can use to place an order on our website. Note that there is a 5-6 week lead time.
Please let us know if you have any questions.