For the 2006 Lexus IS 250, the low-beam bulb depends on the factory headlight system. Models with halogen headlights use H11 low beams, while models with HID headlights use D4S low beams. Confirm the headlight type before ordering, since these bulbs are not interchangeable.
The high-beam headlight uses a 9005 bulb. The fog light is listed for a 9006 LED bulb, providing an LED-specific replacement option for that application.
Other notable exterior fitments include 7440A bulbs for both the front and rear turn signals, 921 bulbs for the reverse lights, and 168 bulbs for the parking and license-plate lights. The front and rear side markers use 194NA bulbs. Interior applications include 194 for the courtesy light, DE3021 for the dome light, 37 for the glove-box light, 168 for the map and other interior lights, and DE3022 for the trunk light.