1980s aluminium window balance spring parts

Thanks for writing in. See our S380-28 or S385-28. The only difference between these two balances is the 'depth' of the bottom nylon fitting. Compare both with your old hardware to see what matches best. You will need to select a stamp option. Look for a stamp code on your balance's metal channel. If there is none, weigh your window sash. You can then match that exact weight with one of the weight ranges listed alongside each stamp option on the product page.

You got it! Please let us know if you have any other questions, we're more than happy to help as best as we can.