Window balance from old vinyl window

Thanks for writing in. See our S351-25 or S390-25 Channel Balances. The only difference between these two balance Series is the 'depth' of the bottom nylon shoe. The Series 351 bottom nylon shoe has a depth of 1", whereas the Series 390 bottom nylon shoe has a depth of 1-1/8". Compare with your old balances and see what you think matches best. You will need to choose a stamp option of 2430. Let us know if you have any questions.