What channel balance would I need to replace this?

Hello there!

Thank you for reaching out to us. I'm afraid this balance is too damaged to identify. In order to help, we would need you to remove an undamaged assembly along with any end fittings or attachments that may still be in the window track.

That's odd, there should be some type of shoe or attachment. Is there a part that the hook in your photos engages with? Can you show us a photo of it? 

Thank you for the additional photos! This is a huge help. We've seen this window and balance assembly before but we, unfortunately, don't sell an exact match. The best we can offer is our Series 770 but with the terminal clip swapped out for the 62-105 hook. We can do this via custom order which is nonrefundable. It should work to replace the balance you have here but please note that the Series 770 is designed to install head-on into the jamb. It screws straight in, not from the sides. With that said, it will be difficult to install but not impossible. 

Does this sound good to you? If it does, I will need you to weigh the window sash and tell me the precise weight. The stamp on your balance differs from the ones the Series 770 uses so we will need to re-calibrate the proper spring strength. Can you also tell me the number of balances you'd like to order? 

Thanks for confirming! I just still need the sash weight in order to get this moving for you. 

The Series 770 is installed with the exposed spring side of the channel pressed against the jamb, while your old balance installs on the sides of the jamb. 

Great. I'll email you a purchase link and price quote for (2) S770-29 balances with the 62-105 hook attached and a 29C stamp. A pair of balances with this stamp will support a sash weighing 18 to 23 pounds. 

It won't be impossible to install this balance but it will be a little tricky as we discussed before. Another customer with the same balance said they had trouble screwing it in from the side since there wasn't much space. With that said, you may want to contact a local professional who can do the job for you.