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.
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.