The National Motor Freight Traffic Association (NMFTA) annually publishes a list of freight class designations, codes, and subclasses for commonly shipped items (https://classit.nmfta.org/). To access this list, you are required to pay a subscription fee. Learn more about freight classes for free on our freight classes pages.
The class determines the cost of the shipping. The lower the class, the lower the cost.
The NMFC freight class for baseballs is 85.