Bob from SWISCO responded:
April 8, 2019
Thanks for posting. Based on your information, it sounds like you need an S900-29 Tilt Window Spiral Balance. Your orange tip is most likely a red tip: orange tips are almost always red tips that have either faded over the years, or just had a slightly different hue depending on the manufacturer. If your window sash weighs 18 lbs, a Red Tip balance should be work well for you, as they are meant to support a sash weight in the range of 10 through 22 lbs. |