Balance identifier

There is a chance the Series 380 or Series 385 could be the replacement you need. Although, I'll need to see a photo of the spring side of the balance to confirm if they are correct. I'm particularly looking to see the bracket connecting the spring and the string.

Please also confirm the stamp/marking from the metal channel.

Thanks for confirming. This balance can be replaced with either the S380-22 or the S385-22, as you mentioned. To determine the series, you'll need to confirm the depth of the bottom shoe.

Since the channel doesn't have a stamp, you'll need to confirm the exact weight of the sash. There is a chart below the product description of the balances. It lists the weight range each stamp can support.

Comparison of the S378, S380 and S385 balance shoes.

Okay, great. As shown on the diagram, you'll need the S385-22. For the stamp, you'll likely need the 2120 option but it is encouraged to double check that the sash weighs between 8 to 12lbs.