921 bulbs are most often used as backup bulbs, but can also be used in tail and side marker lamps on some cars. They are the same base as a 194 bulb, but the bulb segment is larger and has higher wattage. The 2008-2014 WRX sedan and 2011-2014 STI sedan use these for backup bulbs.

The bulb length (above the base) on these is about 1 3/8". Make sure there is enough room in your bulb housing.

This bulb design packs a lot of LED in a small space. It should be used for short periods of time, and not be left constantly on. (It will overheat and start to flicker.)

One-year replacement warranty. Set of two super-white bulbs.