Sealed Beam Inserts for Ø 4-1/2” Headlights

After U.S. drivers (Harleys included) had to deal for decades with various, mutually incompatible headlight bulbs that were often poorly adjusted, the Department of Transportation stepped in from 1940 onward and promoted the Sealed Beam system developed by General Electric as a de facto standard.

“Sealed Beam” means that the lens, reflector, and filament, together with their electrical terminals, form a permanently sealed lighting unit. In case of failure, the bulb is not replaced; instead, the entire headlamp unit is replaced.