11 inch 1 inch bottom piece width

Thanks for your post! I believe your balance can be replaced with the S380-11. Be sure to double check that the length of the channel is 11", excluding the top and bottom attachments.

Close up view of the S380 balance shoe.

To determine the correct stamp option, you'll need to look for the stamp on the other side of the balance. If yours does not have one, you'll need to confirm the exact weight of the window sash. 

There is a chart below the product description of the balances that lists the weight range each stamp will support.