Window balance has no markings please help ID

Thanks for reaching out! We don't have and don't think this balance system is still being made today. We suggest a replacement balance system, Series 795-23. You would need to weigh the sash for the spring weight. To install, you would twist the bottom T-Lock into the track and screw the top clip of the balance cord at the top of the window track using the balance screw plug. Let me know if you have any questions.