Porsche Boxster front and rear side marker bulbs utilize 12961 and 12821 sizes respectively, with each bulb size corresponding to specific marker locations on the vehicle. The replacement chart covers 1997 through 2004 production years and details bulb size specifications for side marker applications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Porsche Boxster uses the 12961 bulb in the front side marker position across all model years from 1997-2004.
The rear side marker position across the same 1997-2004 model year span calls for the 12821 bulb.
Both the 12961 and 12821 are Philips part numbers belonging to the T10 miniature wedge bulb family, which is one of the most widely used bulb types in automotive lighting applications.
The T10 designation refers to a tubular bulb with a nominal width of 10 millimeters, commonly found in low-intensity positions such as side markers, parking lights, and interior lamps.
Both bulbs share an identical W2.1x9.5d wedge base, meaning the physical base construction is the same between the front and rear side marker bulbs on the Porsche Boxster.
The W2.1x9.5d base is a wedgetype connection with no separate metal contacts, as the electrical connection is made directly through the wedge-shaped glass pinch at the base of the bulb.
Both bulbs operate at 12 volts and 5 watts, which are standard ratings for low-wattage automotive marker lighting on 12-volt vehicle electrical systems.
Despite sharing the same T10 form factor, base type, voltage, and wattage, the 12961 and 12821 carry distinct Philips part numbers, indicating they are catalogued separately for front and rear fitment on the Porsche Boxster.