Which coil balance? S161-06 or 15-087?

Hey there,

Thanks for reaching out! Your coil balance housing looks more like the 15-087 Coil Housing Pivot. The biggest difference between this housing and the Series 161 is the thickness.

To confirm that the 15-087 is the correct replacement, carefully compare the dimensions shown below. Although, I am confident these are the replacement you'll need.

Detail of 15-087

This coil housing is compatible with the Series 180 coil balance spring. Since your window is 11.6lbs and you have a 6lb coil, you'll need the S180-6. The metal mounting bracket that secures the coil in the window channel is part 16-024.