I need help figuring out what spiral balance I need

Thanks for posting. Can you confirm the diameter of your outer balance tube? Can you also tell me if your window is tilt or non tilt? Finally, what is the weight of your sash?

Thanks! See our S400-20 spiral balance. This may be what you need. I would recommend trying your best to weigh the sash on a scale to determine the best color tip option. "White" is relatively uncommon these days, and the way manufacturers designate spring strength is different than they did once upon a time. In other words, your White tip may indicate an entirely different spring strength than White tips made today. Knowing the weight of your sash will clear it up, though.