27" & 29" Replacement Balance Inquiry

A quick learner from Irvine, California says:
November 29, 2017
Hello,
I need to get one 27 inch and three 29 inch balances. But I want to be 100% sure of the one I am supposed to order. Can you please tell the exact model I should order? Note - there are no markings / stamps on these current ones. I am guessing the 19-26 lbs rating will work.

Thank you!!
User submitted photos of a window balance.
Profile picture of Paul
Paul from SWISCO responded:
December 5, 2017
I agree, our S350-27 and S350-29 look like the best matches. However, you should check the stamps on your old balances to confirm the best option. If you have no stamps, or if you aren't sure what they mean, you should weigh your sash on a scale to confirm the exact weight. We do not recommend estimating your sash weight in this case.
27" Series 350 Channel Balance
27" Series 350 Channel Balance
S350-27
$10.77
29" Series 350 Channel Balance
29" Series 350 Channel Balance
S350-29
$11.10
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.