Replacement Block and Tackle Channel Balances Balances

Thanks for posting. This looks like a Series 770 Channel Balance. Measure the metal channel to determine the length you need. You then have to choose a stamp option, which reflects the strength of the balance. At least in the photos you show, the stamp on this balance is a bit unusual. To know what stamp to pick, weigh the window sash the balances support. You can use that exact weight to choose the right stamp option. Let us know if you have questions.

Thanks for getting back to me. If the metal channel is 28" long, see the S770-28. For a stamp option choose 28B, which designates a balance that can support a window sash in the weight range of 12 through 18 pounds.