The International S102 uses a 198 bulb size for both front and rear turn signal applications. The replacement chart covers 1956 to 1957 model 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 International S102 uses the 198 bulb in both the front and rear turn signal positions across the 1956-1957 model years.
The 198 is classified as a miniature wedge bulb in the T5 form factor, operating at 12 volts and 2 watts.
The T5 designation refers to the tubular glass envelope width, expressed in eighths of an inch, placing the envelope at approximately 5/8 of an inch wide.
At 2 watts, the 198 is a very low-output bulb, consistent with indicator and signal applications rather than illumination functions.
The 198 bulb conforms to ANSI standards recognized in both the United States and Canada, indicating a standardized specification shared across North American markets.
The wedge base design of the 198 means the bulb is held in its socket by the tension of the base itself, with no separate metal bayonet or screw fitting involved.
All four turn signal positions on the International S102, front left, front right, rear left, and rear right, share the same 198 bulb specification, meaning a single bulb type serves the entire turn signal circuit.
The Light Duty classification associated with the 198 bulb across all listed positions reflects the vehicle trim or weight rating category to which these fitments apply.