window balance

Hello!

It's tough to say from these photos but it looks like your balance may have a 15-043 terminal clip which is used with the Series 770 channel balance. I recommend reviewing the specifications for these parts to confirm they match your old hardware.

Your balance should also measure on an even inch so you'll want to double check this measurement to be safe. Make sure to measure only the metal channel when determining length. If there aren't any stamps on the metal channel, you will need to weigh your sash on a scale. There's a chart under the product description on the Series 770 store page that will indicate what spring strength option you'll need based on your sash weight.