Channel Balance Part recommendation

A home owner from cupertino, ca says:
I am writing to figure out what channel guide do I need to buy for the following milgard windows

h-c40-54x90, 5220/5270
channel guide seems 1/2" wide and only has the following markings on it
20 9 JQ CALDWELL

I measured it and it seems to be about 21" long.

What should i go with?
Thumbnail of the uploaded file named PXL_20210713_200907149.jpg
Thumbnail of the uploaded file named PXL_20210712_135202282.jpg
Profile picture of Emily
Emily from SWISCO responded:

Hello!

We'd be happy to help but we'll need you to remove an undamaged balance with the end attachments intact to compare to our inventory. Check out the video below, it'll explain exactly what we need to see.

A home owner from cupertino, ca says:
More photos of the actual channel. Lookign at the video now.
Thumbnail of the uploaded file named PXL_20210716_160726464.jpg
Thumbnail of the uploaded file named PXL_20210716_160729823.MP.jpg
Thumbnail of the uploaded file named PXL_20210716_160737385.jpg
Thumbnail of the uploaded file named PXL_20210716_160740016.jpg
Profile picture of Emily
Emily from SWISCO responded:

Thanks for the additional pictures!

With this combination of attachments, you could have either an S380-21 or S385-21 channel balance. You’ll need to measure as shown below. The Series 380 has a 1" bottom attachment, and the Series 385 has a 1-3/32" attachment. You'll also need to remove and weigh your sash to choose the appropriate spring strength option. There's a chart on the S380 and S385's product page that shows you which option you'll need based on the weight of your sash.

If you have any further questions just let us know. 

Comparison of the S380 and S385 balance shoes.
Comparison of the S380 and S385 balance shoes.
How to Identify Replacement Channel Balances
How to Identify Replacement Channel Balances
VIDEO
WATCH >
How to Replace a Non-Tilt Channel Balance
How to Replace a Non-Tilt Channel Balance
VIDEO
WATCH >
How to Repair a Jammed Window
How to Repair a Jammed Window
VIDEO
WATCH >
How to replace a non-tilt channel balance
How to replace a non-tilt channel balance
GUIDE
READ >
Choosing a Non-tilt Channel Balance: What Will We Need?
Choosing a Non-tilt Channel Balance: What Will We Need?
GUIDE
READ >
Reply to Thread
Use this form to ask a follow-up question or to share your experience regarding this subject.
(your email address will be kept private and is only used to inform you when a response has been made)
Current wait time is 3-4 business days
We promise that one of our experts will personally get back to you as soon as they are able. Thank you very much for your patience and understanding. If your inquiry is time-sensitive, please feel free to reach us at (888) 991-1929 or at help@swisco.com.