Need to replace my channel balance

A home owner from lake worth, FL says:
December 12, 2016
Dear sir

Enclosed please see the pics for my home's broken channel balance. I need to replace them and please let me know which model number or link to purchase. The length is 27", width is 1/2". It looks like series 377 but not sure. Also I did not find any stamps or markings on it. So won't be able to order. Thanks.
User submitted image of their window hardware.
Profile picture of Paul
Paul from SWISCO responded:
December 14, 2016
I agree, the S377-27 looks to be a good match. If your balance has no stamps on it, then you will need to weigh your sash on a scale to determine the best spring strength option.
27" Series 377 Channel Balance
27" Series 377 Channel Balance
S377-27
$10.77
Top Sash Guide Pair, Pan Am
Top Sash Guide Pair, Pan Am
18-042
$1.97
Pan Am Take Out Clip
Pan Am Take Out Clip
16-023
$1.17
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