The International B122 front and rear turn signal bulbs both utilize a 198 size bulb specification. The 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 198 bulb is the sole bulb type listed across all turn signal positions for the International B122, appearing in both the front and rear turn signal applications for 1959-1960.
The 198 bulb follows the ANSI standard, meaning it conforms to the American National Standards Institute specifications recognized across the United States and Canada.
It is a miniature wedge-base bulb, classified under the T5 designation, which refers to a tubular lamp body approximately 5/8 of an inch wide.
The 198 bulb operates at 12 volts and draws 2 watts, placing it among the lower-wattage signal bulbs used in automotive applications of that era.
The Light Duty classification noted in the specifications indicates the B122 variant for which these bulb sizes apply, distinguishing it from any heavier-duty configurations that may use different components.
The wedge base of the 198 bulb means it is held in its socket by the tension of the base contacts rather than by a bayonet or screw mechanism, a design that affects socket compatibility when sourcing replacements.
The front and rear turn signal positions on the International B122 share an identical bulb specification for both listed years, indicating no positional differentiation in bulb requirements between the two locations.