The International R120 uses a 198 bulb size for both front and rear turn signal applications. The replacement chart covers 1953 to 1955 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 198 bulb is the sole bulb type listed across all turn signal positions in the International R120 specifications, appearing in both front and rear applications for the 1953-1955 model years under the Light Duty classification.
The 198 bulb follows the ANSI standard, meaning it conforms to a recognized North American specification used across the United States and Canada.
The 198 is a miniature wedge bulb, designated by the T5 envelope shape. The T5 designation refers to a tubular glass envelope that is 5/8 of an inch wide.
The 198 bulb operates at 12 volts, which is consistent with the standard electrical system voltage found in most conventional automotive applications of that era.
At 2 watts, the 198 bulb draws a very low amount of power, which is characteristic of small indicator and signal lighting rather than primary illumination functions.
The front and rear turn signal positions on the International R120 share the same bulb specification across all listed years, indicating that a single bulb type serves both locations without variation.
The wedge base design of the 198 bulb means it is held in its socket by the tension of the base itself rather than by a bayonet or screw mechanism, which is a distinct fitment characteristic relevant to socket compatibility.
Because the 198 is a wedge-type bulb, it is not directly interchangeable with bayonet-base bulbs such as the 1156 or 1157, even if voltage ratings were otherwise similar.