1401.05(c) Classification and Plurality of Uses 
A product that has a plurality of uses or aspects is ordinarily classified in a single class. Ex parte Schatz, 87 USPQ 374 (Comm’r Pats. 1950). However, if it can be shown that a product has a plurality of uses or aspects so that two or more classes apply, multiple classification may be permissible. If a product is normally classified in a particular class, an applicant cannot obtain registration in another class merely by identifying an ultimate use of the product in goods that fall in the other class.
Example - Essential oils are classified in Class 3. This item cannot be classified in Class 1 with an indication that it is used in the manufacture of other finished products. Raw or unfinished materials that are used in the manufacture of other finished products may be classified in Class 1. However, an item like essential oils, which is always classified in Class 3 regardless of its ultimate use, cannot be transferred to Class 1 by adding Class 1 qualifying language.
When classification in multiple classes is appropriate, the identification must clearly indicate the basis for multiple classifications with language that is appropriate for the respective classes. Identical language cannot be used. For example, the USPTO will not accept the identification "clock radios," because it is unclear what the goods are and in which class the goods fall - Class 9 for radios or Class 14 for clocks. However, the applicant may adopt either or both of the following identifications - "radios incorporating clocks" in Class 9 or "clocks incorporating radios" in Class 14.
Certain services may also be classified in multiple classes on the basis of the purpose for which the service activity is rendered. While services are in principle classified according to the branches of activities specified in the headings of the service classes and in their Explanatory Notes, if an activity is not specified by any class heading, the purpose may determine classification.
Example – Layout services are classified in Class 35 when specified to be "for advertising purposes" and are classified in Class 41 when specified to be "other than for advertising purposes."
In an application under §1 of the Trademark Act, the specimen(s) should reflect acceptable use of the mark for each of the specified classes and the record must not indicate that the product has only one use or aspect. See The Procter & Gamble Co. v. Economics Laboratory, Inc. modified without opinion, 495 F.2d 1360, 181 USPQ 722 (C.C.P.A. 1974); In re International Salt Co., 166 USPQ 215 (TTAB 1970) ; Mead Johnson Co. v. Watson, 112 USPQ 284 (D.D.C. 1957) , aff’d 253 F.2d 862, 117 USPQ 13 (D.C. Cir. 1958).
Where a single specimen supports multiple classes, the examining attorney need not require multiple copies of the specimen. See TMEP §904.01.
Where a single product or service is classified in more than one class, the applicant must also comply with all other requirements for multiple-class applications. See TMEP §1403.01.