BPC §14235: The classification of goods and services shall conform to the classifications adopted by the United States Patent and Trademark Office.

The classification of goods and services shall conform to the classifications adopted by the United States Patent and Trademark Office. A single application for registration of a mark may include any or all goods upon which, or services with which, the mark is actually being used indicating the appropriate class or classes of goods or services. When a single application includes goods or services that fall within multiple classes, the secretary may require payment of a fee for each class.