The International R131 front and rear turn signal bulbs both utilize a 198 size bulb specification. The replacement chart covers vehicle production spanning 1953 to 1955.
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 for the International R131, appearing in both front and rear applications for the 1953-1955 model years.
The 198 bulb follows the ANSI standard, which is the recognized specification framework used in the United States and Canada for automotive lighting components.
The 198 bulb is a T5 miniature wedge type, meaning it uses a wedge-shaped base rather than a bayonet or screw fitting, and the T5 designation refers to a tubular envelope that is five-eighths of an inch wide.
The 198 bulb operates at 12 volts, consistent with the standard electrical system voltage found in most mid-20th century light-duty vehicles.
At 2 watts, the 198 bulb draws very low power, which is characteristic of indicator and signal lighting rather than high-output illumination functions.
All listed applications for the International R131 are designated as Light Duty, and this classification applies uniformly across both the front and rear turn signal positions for the full 1953-1955 span.
Because the 198 bulb uses a wedge base, it is not interchangeable with bayonet-base bulbs of similar voltage or wattage, as the physical retention and contact mechanisms differ between those base types.