Tennessee Code Title 2. Elections § 2-6-501

For persons voting absentee by mail or registering by mail from outside the territorial limits of the United States and for all armed forces personnel, there shall be printed across the face of each envelope in which a ballot or any registration material is to be sent the words “Official Election Balloting Material--Via Air Mail”, or similar language. Furthermore, there shall be printed the words “Free of United States Postage, Including Air Mail.”