CALIFORNIA WARNING: This product can expose you to chemicals, including lead and DEHP, which are known to the State of California to cause cancer and birth defects, or other reproductive harm. For more information, go to https://www.p65warnings.ca.gov.
Extension spring used on early Williams 50 step unit assemblies and others.
Reference:
10A-183C-6510 non-resetting 50 step unit with bellC-6510A non-resetting 50 step unit without bellC-6494 resetting 50 step unit