Ohio Rev. Code § 3511.06
The return envelope provided for in section 3511.05 of the Revised Code shall be of such size that the identification envelope can be conveniently placed within it for returning the identification envelope to theoffice of the board of elections. The envelope in which the two envelopes and the uniformed services or overseas absent voter's ballots are mailed to the elector shall have two parallel lines, each one quarter of an inch in width, printed across its face, paralleling the top, with an intervening space of one-quarter of an inch between such lines. The top line shall be one and one-quarter inches from the top of the envelope. Between the parallel lines shall be printed: "official uniformed services or overseas absent voter's balloting material--via air mail." The appropriate return address of the board of elections shall be printed in the upper left corner on the face of such envelope. Several blank lines shall be printed on the face of such envelope in the lower right portion, below the bottom parallel line, for writing in the name and address of the elector to whom such envelope is mailed.
R.C. § 3511.06