The Subaru WRX side marker utilizes a 12961 bulb size for the lighting assembly. Data for the specific bulb requirements covers the 2023 through 2023 range of production.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Subaru WRX side marker specifications reference two bulb types across the listed model years: the 12961 and the 168. Both are T10 miniature wedge bulbs operating at 12 volts, making them physically similar in form factor despite carrying different part designations.
The 12961 is a Philips-assigned part number rather than an ANSI industry standard designation. It specifies a W2.1x9.5d base and a 5W output, which are the defining electrical and mechanical characteristics of that bulb.
The 168 carries an ANSI standard designation recognized in the United States and Canada. It shares the T10 wedge form with the 12961 but is rated at 4.9W, a slight difference from the 5W rating of the 12961.
For the Subaru WRX front side marker, the 2020-2022 model years use the 12961 bulb, while the 2018-2019 model years use the 168 bulb. This represents a change in the specified bulb between the 2019 and 2020 model years.
The rear side marker on the WRX follows the same split: the 12961 is specified for 2020-2021, and the 168 is specified for 2018-2019.
Although the 12961 and 168 share the T10 wedge body style, the difference in base designation is a relevant fitment consideration. The 12961 specifies a W2.1x9.5d base, which is the standard wedge base type for T10 bulbs, and the 168 is also a wedge base, meaning physical fitment into the socket is generally compatible between the two types.
The 0.1W difference between the 12961 (5W) and the 168 (4.9W) is negligible in practical terms, but substituting one for the other across model years should be approached with reference to the year-specific specification, as the manufacturer has designated distinct part numbers for distinct model years.
The front side marker specification for 2022 lists only the 12961, and no rear side marker entry exists for 2022 in the provided specifications.