Goods and services covered by a trademark are categorized into classes depending on the nature of the goods and services. There are 45 different trademark classes. Classes 1 -34 cover various types of goods and classes 35-45 cover various types of services.
You can learn more about the different trademark classes in the Trademark Manual of Examining Procedure and by searching the Trademark ID Manual.
The easiest way to determine what class your goods/services fall in is to search the Trademark ID Manual. Below is a screenshot of a search for “t-shirts” in the Trademark ID Manual. You can see that “T-shirts” is listed as an acceptable identification and is listed in Class 25. If you are having trouble finding an accurate description in the Trademark ID Manual for your goods/services, try describing the goods/services in a different way.
It is possible to use a free-form description of your goods/services if you can’t find an accurate description in the Trademark ID Manual, but the government charges an additional $100 per class if you use a free-form description. Using a free form description requires using a different application type. If you have a multi-class application and one class uses a description from the Trademark ID Manual and the other class uses a free-form description, the additional $100/class government fee will apply to both classes.