The International R131 uses a 194 bulb size for front side marker applications and a 97 bulb size for rear side marker positions. The replacement chart covers 1953 to 1955 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 R131 uses two distinct bulb types across its front and rear side marker positions for the 1953-1955 model years: the 194 at the front and the 97 at the rear.
The 194 is an ANSI-standard miniature wedge bulb in a T10 form factor, rated at 12V and 3.78W, and is designated for the front side marker position on the International R131 (Light Duty) across all three model years covered.
The T10 wedge base of the 194 bulb requires no locking mechanism for retention; the bulb is held in place by the socket walls alone, which is a defining characteristic of the wedge base design.
The 97 is an ANSI-standard single-filament bulb rated at 12V and 13W, fitted with a BA15s bayonet base, and serves the rear side marker position across the 1953-1955 Light Duty R131.
The BA15s designation indicates a single-contact bayonet base with a 15mm collar, which is a mechanically distinct mounting style from the wedge base used by the 194, making the two bulb types non-interchangeable with each other.
At 13W, the 97 draws considerably more power than the 3.78W 194, reflecting the greater luminous output typically required at the rear marker position relative to the front.
The 97 is noted as a variant of the 1156 bulb. While both share the BA15s bayonet base, the 97 and 1156 differ in wattage and light output, and the two are not directly interchangeable despite their physical similarities.
Both the 194 and the 97 conform to ANSI standards applicable in the United States and Canada, indicating that both bulb types follow a standardized specification for base dimensions and electrical ratings within those markets.