The Mercedes-Benz SLK320 front side marker uses a 12961 or 12821 bulb size, while the rear side marker requires a 67 or 12821 bulb size. The replacement chart covers 2001 to 2004 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 Mercedes-Benz SLK320 uses three distinct bulb types across its front and rear side marker positions: the 12961, the 12821, and the 67.
Both the 12961 and 12821 are Philips part numbers designating miniature wedge bulbs of the T10 form factor, each rated at 12V and 5W with a W2.1x9.5d base.
Despite carrying different Philips part numbers, the 12961 and 12821 share identical electrical ratings and the same base type, making them functionally equivalent in voltage and wattage.
The 67 is an ANSI-standard bulb used in the United States and Canada, rated at 12V and 8W, and uses a BA15s single-contact bayonet base, which is physically incompatible with the wedge-style socket required by the 12961 and 12821.
The BA15s base of the 67 bulb is a single-contact bayonet fitting, meaning it cannot be substituted with a T10 wedge bulb without a socket adapter or wiring modification.
The 67 bulb is described as a lower wattage variant of the 1156, which shares the same BA15s bayonet base but draws significantly more power; the two are not interchangeable as direct replacements due to the wattage difference.
For the 2001-2003 Mercedes-Benz SLK320, the front and rear side markers both use the 12821, meaning the same bulb type serves all four side marker positions in those model years.
In the 2004 model year, the front side marker specification changes to the 12961 while the rear side marker changes to the 67, resulting in two different base types being required simultaneously on the same vehicle.