Description
HELLA H4 Headlight (Round) 12v 7
Sealed beam headlamps were introduced in the 1930s to provide a consistant quality of headlamps. Prior to that, headlamp design was left up to the vehicle manufacturer and lighting ability varried greatly.
The problem with sealed beams is that the lens, reflector and fillaments are all part of a bonded assembly. When the filament burns out, the entire lamp is discarded. Consequently, the sealed beam has become a commodity. As long as it meets the DOT standard, the only thing that matters is low cost. The DOT standard allows for a very loose pattern with a wide transition from dark to light. Many sealed beams still conform to the antiquated pre 2000 DOT standard that required 20% of the light go up to illuminate overhead signs.
All of this results in lamps that dazzle oncoming traffic and at the same time supply poor illumination of the road. The sharp low beam cutoff of Hella ECE lamps makes the areas that are supposed to be dark darker and the lighted areas to be brighter. We say that our lamps are four times brighter on low beam and twice as bright on high beam. Refer to the Isolux drawings at left.