The Mazda 323 uses the 9004 bulb for both high beam and low beam headlights across the 1986-1994 model years.
The 9004 is a dual-filament halogen bulb, meaning a single bulb unit contains two separate filaments: one rated at 65W for high beam output and one rated at 45W for low beam output.
Because both the high beam and low beam positions share the same 9004 bulb type, a single bulb replacement serves both functions within each headlight housing.
The 9004 operates on a 12V electrical system, which is standard for passenger vehicles of this type.
The 9004 uses a P29t base, which is a specific connector configuration. Bulbs with different base types are not physically interchangeable with this socket, regardless of wattage or voltage ratings.
The 9004 is an ANSI-standardized bulb type recognized in both the United States and Canada, meaning it conforms to a defined set of electrical and physical specifications rather than being a proprietary part number.