The Ducati Monster 620 headlight uses a 9003 bulb size for both high beam and low beam functions. The replacement chart covers 2002 to 2006 model years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Ducati Monster 620 uses the 9003 bulb type for both high beam and low beam headlight positions across the 2002-2006 model years.
The 9003 bulb is a dual-filament halogen type, meaning a single bulb contains separate filaments for high and low beam functions within one housing.
Because the 9003 bulb serves both the high beam and low beam positions on the Monster 620, both headlight functions rely on the same physical bulb unit.
The 9003 standard is electrically and physically equivalent to the H4 designation used in many international markets, making the two interchangeable in practice.
The 9003 bulb operates at 12 volts, with a rated output of 60 watts on the high beam filament and 55 watts on the low beam filament.
The base configuration of the 9003 bulb follows a P43t designation, which refers to the three-pin bayonet-style base that locks the bulb into its socket at a fixed rotational orientation.
The fixed rotational orientation of the P43t base is a critical fitment characteristic, as it ensures the filaments are correctly aligned within the reflector housing for proper light projection.
Substituting a single-filament bulb in place of the 9003 would not satisfy both beam functions simultaneously, as the dual-filament design is integral to how the headlight assembly operates on this model.