For the 2002 Hyundai Elantra, the supplied fitment data lists an H1 bulb for the high beam. No low-beam bulb is provided in this data, so verify the low-beam housing and existing bulb before ordering a replacement. Fog-light fitment is listed as either H3 or H3C; check the fog-light assembly to confirm which version your vehicle uses.
Other useful exterior bulb specifications include 2357A for the front turn signal and parking light, 1156 for the reverse light and center stop light, and 2357R for the brake and tail lights. The rear turn signal uses 1156A, while the front side marker uses 194NA.
For convenience lighting, the dome light uses DE3175, and the courtesy and trunk lights use DE3022. License-plate lighting is listed with either 168 or 917, so compare the installed bulb or socket before purchasing.