1/2" Channel Balance replacement

A handy person from South Bend, IN says:
I need help identifying the type of channel balance replacement needed for my assembly (see photos). It is a 26"L, 1/2"W channel balance with #2540 weight rating engraved on it. I will need two.
Profile picture of Casey
Casey from SWISCO responded:

Hello,

We'd be happy to help you identify your balance, but it can be very difficult to identify a balance that is still installed in the window. Could you confirm whether the top nylon attachment on your balance has the plastic wings that jut out to the sides like the bottom attachment? Sending us another picture of the entire balance removed from the window would also help us confirm this. Thank you!

Profile picture of Tom
Tom from SWISCO responded:

Yes, that is S350-26. I'll flag down a more experienced researcher to look into that nylon part, though. I'm not sure what it does. What function does that part serve?

A handy person from South Bend, IN says:
Hi Casey,
It is whatever balance that uses the nylon pieces 15-004 and 19-002 I just ordered last week. I used the recently ordered nylon parts in an extra balance that just got installed and it worked. I believe it is the "26" SERIES 350 CHANNEL BALANCE," but want to verify prior to ordering.
A handy person from South Bend, IN says:
Also, I just realized after the installation of the new channel balance that I am missing another part. I unfortunately don't know the name of it. It is circled in red in the attached photos. I will need one of these too. Thanks!
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 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
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.