Constant force balance system

Thanks for posting. Your pivot shoe looks like our 15-180 Coil Balance Shoe; just double check the dimensions to see if they match your old part. This shoe is compatible with our Series 180 Coil Springs. Each spring in this Series supports a particular amount of weight, and you will need to order the right combination to match your window sash's overall weight. For example, let's say your window weighs 20 lbs. You would want (4) of the S180-540, which supports 5 lbs of weight. You would then install two of each on either side of the window sash, so that each side supports 10 lbs, for a total equal to the overall sash weight of 20 lbs. If you need figuring this out just let us know.

Very well! You can order our 15-180 shoe and our S180-9 9 lb Coil Spring from our shape. As far as a plastic piece at the bottom of the window, I am not certain what you are referring to. Do you simply mean something like our 15-186 Coil Balance Clip with the 15-182 Coil Bushing? Or were you referring to something else? Take a picture of this piece so we can see for sure. Thanks.