Fiat 124 Spider front and rear side marker bulbs use a 12961 size replacement bulb. The chart covers 2017 to 2020 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 Fiat 124 Spider uses the 12961 bulb for both front and rear side marker positions across the 2017-2020 model years.
The 12961 is a Philips part number designating a miniature wedge bulb in the T10 form factor, rated at 12 volts and 5 watts.
The T10 bulb uses a W2.1x9.5d base, which is a wedge-style base that seats by friction rather than by a bayonet or screw mechanism.
The front side marker specification for the 2017-2020 Fiat 124 Spider carries a "With LED Headlamps" condition, meaning the 12961 fitment applies specifically to vehicles equipped with LED headlamps.
The rear side marker position carries no such conditional notation, and the 12961 bulb applies to all 2017-2020 rear side marker fitments without restriction.
At 5 watts, the 12961 is a low-output bulb consistent with side marker and parking light applications, where high luminous intensity is not required.
The W2.1x9.5d base designation is standardized under international automotive bulb classifications, and the 12961 is interchangeable with other T10 wedge bulbs sharing that base type, provided the voltage and wattage ratings are compatible with the vehicle circuit.