Ohio Rev. Code § 4503.22
The identification license plate shall consist of a placard upon the face of which shall appear the distinctive number assigned to the motor vehicle as provided in section 4503.19 of the Revised Code, in Arabic numerals or letters, or both. The dimensions of the numerals or letters and of each stroke shall be determined by the director of public safety. The license placard also shall contain the name of this state and the slogan "BIRTHPLACE OF AVIATION." The placard may be made of steel, aluminum, plastic, or any other suitable material, and the background shall be treated with a reflective material that shall provide effective and dependable reflective brightness during the service period required of the placard. Specifications for the reflective and other materials and the design of the placard, the county identification stickers as provided by section 4503.19 of the Revised Code, and validation stickers as provided by section 4503.191 of the Revised Code, shall be adopted by the director as rules under sections 119.01 to 119.13 of the Revised Code. The identification license plate of motorized bicycles or mopeds, motor-driven cycles or motor scooters, autocycles, cab-enclosed motorcycles, and motorcycles shall consist of a single placard, the size of which shall be prescribed by the director. The identification plate of a vehicle registered in accordance with the international registration plan shall contain the word "apportioned." The director may prescribe the type of placard, or means of fastening the placard, or both; the placard or means of fastening may be so designed and constructed as to render difficult the removal of the placard after it has been fastened to a motor vehicle.
R.C. § 4503.22