Tilt Spiral Rod ID

Thanks for posting. While I can't be entirely certain without pictures, based on the information provided it sounds like you have an S900-29 3/8" Spiral Balance for a Tilt Window. The white tips are a little different than the other color options, and can refer to a variety of window sash weights depending on when they were made. The best way to know what color tip option to select is to weigh your window sash. You can then match that precise weight with one of the weight ranges listed with each color tip option on the S900-29 page. Let us know if you have any questions.