Window Coil Balance (I think)

Hello!

The pivot shoe you have here appears to be the 15-199. This is used with the 1/2" S160 and 3/8" S165 coil springs. From the looks of your cover, the 15-205, I suspect the coil spring band is 3/8" wide but please correct me if I'm wrong. 

Can you weigh the window sash on a scale and tell us the precise weight? We can calculate what spring weights you'll need from there. 

You can use three S165-3 3-pound springs on both sides of the window. This will total 18 pounds of overall support which should be fine so long as the spring weights are within a pound of the sash weight. 

Your dimensions are off from the 15-199 though. To get the most accurate measurement, you'd want to remove the old pivot shoe from the window track. The video below will show you how to do so using the cut out method. 

Unfortunately, we are not able to make out exact dimensions from photos but the 1-1/4" width and 17/32" depth would be the key measurements. As long as they match your part, you should be good to go. 

We're happy to help. Just let us know if you need anything else!