International ProStar Turn Signal Bulb Size

The International ProStar front turn signal bulb uses a 3457NA size bulb. The replacement chart covers vehicle production spanning 2008 to 2018.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Front Turn Signal

Years	Bulb Size
2015-2018	3457NA (With Halogen Capsule Headlamps)
2008-2014	3457NA

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament wedge bulb (T25), natural amber glass. 12V, 27W/7W.	3457NA

The 3457NA is the sole front turn signal bulb type specified for the International ProStar across all listed model years, spanning 2008-2018.
The 3457NA is an ANSI-standardized bulb type recognized in both the United States and Canada, indicating a North American fitment standard.
The 3457NA carries a T25 wedge form factor, which refers to a tapering plastic wedge base rather than a metal bayonet or screw base, and is inserted directly into a matching socket without a separate holder.
The bulb operates on a 12-volt electrical system, consistent with standard commercial vehicle architecture.
As a dual-filament bulb rated at 27W and 7W, the 3457NA supports two independent brightness levels within a single housing, a configuration commonly used where one circuit serves turn signaling and another serves a parking or running light function.
The "NA" suffix in the 3457NA designation denotes natural amber glass, meaning the amber color is produced by the glass envelope itself rather than by an amber-tinted lens or housing.
For the 2015-2018 International ProStar, the 3457NA fitment is specifically noted as applying to vehicles equipped with Halogen Capsule Headlamps, indicating a conditional compatibility tied to the headlamp system installed on the vehicle.