The Harley-Davidson FXEF Fat Bob uses an H5006 bulb size for both high beam and low beam headlight applications. The replacement chart covers 1979 to 1981 model years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The H5006 is the sole bulb type listed across all positions and years in these specifications, appearing in both the high beam and low beam headlight positions for the Harley-Davidson FXEF Fat Bob across the 1979-1981 model years.
The H5006 is a sealed beam unit, meaning the lens, reflector, and filament are fused into a single glass assembly. When the filament fails, the entire unit requires replacement rather than an individual bulb.
The H5006 follows the ANSI standard recognized in the United States and Canada, designating it as a 5.75-inch round sealed beam format with a 12-volt operating specification.
Because the high beam and low beam positions share the same H5006 designation across all listed years, the FXEF Fat Bob uses a single sealed beam unit that serves both lighting functions rather than separate bulbs for each beam mode.
The 5.75-inch round form factor of the H5006 is a standardized size within the ANSI sealed beam system, which means units from different manufacturers sharing this designation are generally interchangeable provided they meet the same voltage and beam pattern ratings.