Mercedes-Benz C300 front and rear side marker bulbs utilize a 12961 bulb size across both positions. The replacement chart covers vehicle production spanning 2008 to 2014.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz C300 uses the 12961 bulb for both front and rear side markers across the 2008-2014 model years.
The 12961 is a Philips part number designating a miniature wedge bulb in the T10 form factor with a W2.1x9.5d base.
The W2.1x9.5d base is a wedge-style base type, meaning the bulb is held in its socket by the tension of the glass envelope itself rather than by a separate metal base with pins.
The T10 designation refers to the tubular glass envelope of the bulb, which is 10 millimeters wide.
The 12961 operates at 12 volts and 5 watts, placing it in the low-wattage category typical of marker and courtesy lighting applications.
The front and rear side marker positions on the C300 share an identical bulb specification, making the 12961 interchangeable between both locations on this vehicle.
The T10 wedge format is one of the most widely used miniature bulb types in automotive lighting, and the W2.1x9.5d base is its standardized socket interface across many manufacturers and vehicle platforms.
Because the 12961 is a Philips-branded part number, equivalent bulbs from other manufacturers are typically cross-referenced by the generic T10 or W5W designation, where W5W reflects the wattage and base type in the international naming convention.