What are trademark classes?
The United States Patent and Trademark Office organizes products and services according to specific categories, or classes. There are 45 classes, 34 of which are product classes and 11 of which are service classes. If you want your trademark to cover more than a single product or service, and those products or services fall into more than one class (for example, dog leashes and clothing), additional fees are required for each additional class. The USPTO charges a government filing fee of $350 per class. So, the more classes you include in your application, the more expensive it becomes.