The spring is about 15 inches and hooks into a looks like pulley system that is 1 3/8 inch in length and the other end is around a looks like rivet. So at the pulley system attached to the spring there is a string attached to that pulley and goes to the end of the balance which has a similar pulley attached to the balance with a white plastic piece attached also to the pulley and the balance.
There is a white plastic piece at the top of the metal piece attached to the balance. There are metal clips in the window channel which I have no pictures of.
Can you identify this type of balance.

