Need to replace my Caldwell Balance on a few windows
Thanks for writing in! It looks like you have either the S380-21 with a 1" shoe or the S385-21 with a 1-3/32" shoe. The metal channel of these balances is 21".
To determine which series is needed for your window, look over the dimensions from the diagram below to confirm the depth of your bottom shoe. Let me know if it does not match either measurement.
Once you have confirmed the series you need, you'll need to check your metal channel for any stamps or markings. The stamp is what helps to determine the weight range your balances should be able to carry to support the weight of your sash.
If your stamp does not match any of ours or there are none at all, you'll need to obtain the exact weight of your sash. Then you'll be able to select your stamp option from the chart below your product description. They are listed according to the weight range the options can support.
Unfortunately, I would not be able to confirm that from the photos. You will need to confirm the measurement using the diagram provided above.
Once you've confirmed the series, you'll need to select the 2050 stamp.