Window balancers

A quick learner from Naples Fl. says:
April 30, 2020
1/2 inch wide, 30 1/4 long. The only markings are the numbers 2940 and the letters NM or NN BSI.
Thumbnail of the uploaded file named FE175A10-C85C-4213-B562-BA3A88AD500B.jpeg
Profile picture of Casey
Casey from SWISCO responded:
May 4, 2020
Hello,
We'd be happy to recommend a replacement balance but we will need to see the attachment on the opposite end of the metal channel as well to compare to our replacement options. Also, make sure that you are measuring just the metal channel when determining the length since it would normally be 30" exactly. Thank you!
Profile picture of Casey
Casey from SWISCO responded:
May 4, 2020

Perfect. I believe I see tabs that we commonly refer to as wings on your bottom attachment. If so, take a look at our S377-30 channel balance with a 2940 spring strength option. Please let us know if you have any other questions.

A quick learner from Naples Fl. says:
May 4, 2020
Hi Casey, the metal is exactly 30 inches long. I am attaching pictures of the ends which are plastic.
Thumbnail of the uploaded file named 9D86AD6F-FC25-4A8E-9549-E73FA70C6D40.jpeg
A quick learner from Naples Fl. says:
May 4, 2020
Looks good. I will way the window to make sure that 2940 is right. Thanks
Profile picture of Casey
Casey from SWISCO responded:
May 5, 2020

It never hurts to be thorough. Please let us know if you need anything else. 
30" Series 377 Channel Balance
30" Series 377 Channel Balance
S377-30
$11.52
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.