30" window spring

Thanks for your patience during this busy season. Please confirm the length of the metal channel, not including the nylon fittings at either end. This measurement should check out at 29". If so, see either our S380-29 or S385-29; just be sure that your top nylon fitting has wings like the shoe does, I can't say for sure from your photo. The only difference between these two balances is the 'depth' of the bottom nylon shoe. Compare both with your old hardware to see what matches best. You will need a stamp option of 2840.