Nuprime aluminum double hung window

Thanks for writing in. It looks like you have either the S351-25 with a 1" shoe or the S390-25 with a 1-1/8" shoe. 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. You'll need to select the 2420 stamp.

Comparison of the S351 and S390 balance shoes.

Your top sash guide closely resembles our 18-110. Again, look over the dimensions and compare them to your existing hardware to confirm that this is the right fit for your sash.

Alternate view of 18-110

If your shoe is measuring over 1" then it is likely you'll need the 1-1/8" shoe. It is likely not measuring at exactly 1-1/8" because of the wear and tear on it over the years.

Can you confirm the measurement you are getting?

Thanks for confirming. You should be fine with the 1-1/8" shoe.