Coil Balance Replacement: I think Series 161?

Hi Kevin. The best thing to do is to obtain the exact weight of the window sash, perhaps by lowering the sash onto a bathroom scale. Give us that exact weight, and show us pictures of your old coil balance hardware out of the window, and I should be able to work out what you need. 

Hey Kevin. I'm glad you showed me the pivot shoe, because this is not our Series 161. Judging from the cam, I believe this is a 15-087 shoe. This shoe uses our Series 180 Coil Balances, sold separately. I would absolutely confirm the weight of the sash exactly before proceeding, but if it's 6 pounds, use (2) S180-3 3 pound springs, one for each side of the sash. Let me know if you have further questions.