The International S112 uses a 198 bulb size for both front and rear turn signal applications. The replacement chart covers 1956 to 1957 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 International S112 uses the 198 bulb for both front and rear turn signals across the 1956-1957 model years.
The 198 is an ANSI-standardized bulb type, meaning its physical and electrical specifications conform to a defined North American standard recognized in both the United States and Canada.
The 198 bulb follows the T5 form factor, which refers to a tubular miniature wedge-base design measuring 5/8 of an inch in width at its widest point.
A wedge-base bulb relies on the tension of its flattened glass base to make electrical contact within the socket, rather than using a separate metal cap or pins.
The 198 bulb operates at 12 volts, consistent with the standard electrical system voltage found in most conventional automotive applications.
At a rated output of 2 watts, the 198 is a low-power bulb, which is characteristic of indicator and signal lighting rather than primary illumination functions.
The shared bulb specification across both front and rear positions on the International S112 means a single bulb type serves all four turn signal positions on the vehicle.
The Light Duty designation associated with the 198 bulb in these specifications reflects a vehicle classification rather than a property of the bulb itself.