Identifying the right channel balance for a non-tilt window

Thanks for posting. Your balances look like our S380-18 and S385-18 channel balances. To determine which series you have, you'll need to confirm the depth of your bottom shoe. It should be either 1" or 1-3/32". Take a look at the diagram below for reference.

Comparison of the S378, S380 and S385 balance shoes.

The stamp indicates the weight range your balances should be able to carry but I am unable to cross reference the stamp you have, unfortunately. Once you've determine the balance series, you'll need to obtain the exact weight of the window and then use the chart below the product description to determine which stamp you'll need to select.