Measurements and photos of 7 windows needing balance springs

A quick learner from USA says:
April 15, 2024
Dear Help,
We have 7 M&W double-hung wooden windows needing replacement balance springs. They are original windows, installed in 1992 by the builder.

All 7 windows are 72" tall and 27" wide. The metal springs on each side measure 3/8" wide, while the plastic channels that encase the springs measure 9/16" wide.

Please advise on ALL the parts we need to order for each window.
THANKS

It is a Non-Tilt window.

Unfortunately, I am NOT able to remove the balance spring unit in order to see both ends. All I can see in each window are the broken springs at the top of the upper sash.

As for the length of the plastic tubing of the balance, I can't see below the top of the bottom sash where the channel disappears (see photo). But from the top of the tubing to the bottom sash where it disappears measures 36". How much below that 36" mark the tubing and spring terminate, I have no idea and can't get a visual on it.
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Thumbnail of the uploaded file named Bal2.JPG
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Bob from SWISCO responded:
April 15, 2024

Thanks for posting. This is likely a Series 500 5/8" diameter Spiral Balance, commonly seen with non-tilt wood windows. You will need to remove your existing spiral balances to get the proper length of the outer tube. The guide below will instruct you how to do this. Take a look and let me know if you have further questions. 

Guide: How to adjust a spiral balance on a non-tilt window
How to adjust a spiral balance on a non-tilt window
Bracket, #32
Bracket, #32
17-012
$1.20
Spiral Balance Charging Tool for Non-tilt Windows
Spiral Balance Charging Tool for Non-tilt Windows
75-005
$12.10
How to adjust a spiral balance on a non-tilt window
How to adjust a spiral balance on a non-tilt window
GUIDE
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