Owne Corning double hung installed 2001

Thanks for posting. This looks like it might be our 15-199 Pivot Shoe. Just compare all dimensions just to be safe. This shoe is compatible with either our Series 160 or Series 165 Coil Springs. To my eye I believe you have Series 165 Coil Springs, but which have the cutout further up the tongue and are 3/8" wide; but double-check to confirm. You'll need to look for stamp codes on the springs to determine what spring weights you need. If there are no codes, or you're uncertain, weigh the window sash. Give us that exact weight and we'll work out what you need. Let us know if you have any other questions.

Thanks for the update. With that in mind, I think that the Series 165 coil spring Bob mentioned is worth considering. 

Well for that you would just need to do a little math. If your sash is 20 pounds, then you could use four 5 pound springs; that'd be two on each side. Four 5 pound springs will add up to 20 pounds. With that in mind, I'd recommend our S165-5.