The International B100 uses a 198 bulb size for both front and rear turn signal applications. This replacement chart covers vehicle production spanning 1959 to 1960.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The International B100 uses the 198 bulb for both front and rear turn signals across the 1959-1960 model years.
The 198 is classified as an ANSI standard bulb, meaning it conforms to a defined North American specification recognized in both the United States and Canada.
The 198 bulb follows a T5 miniature wedge form factor, which refers to a small tubular glass envelope measuring 5/8 of an inch in width and a wedge-style base that connects directly without a separate metal cap or pins.
The 198 operates at 12 volts and draws 2 watts, placing it at the lower end of the power range for automotive signal lighting.
The wedge base design of the 198 means the bulb is held in its socket by the tension of the socket walls rather than by a bayonet or screw mechanism, which is a common trait of low-wattage miniature automotive bulbs.
The Light Duty designation associated with the 198 fitment on the International B100 indicates the bulb specification applies to the lighter vehicle configuration rather than a heavier commercial variant.
Because the same 198 bulb size is specified for both the front and rear turn signal positions, no separate bulb type is required when servicing either location on the 1959-1960 B100.