H-7, H4, H1, Vs 9004,9003, etc

[toocrazy2yoo]

The powerbulb site doesn't list bulbs with the same numbers as here in the States. For instance, my car has 9003s..

I gather (but it isn't positivly identified as such) that on powerbulb.com, 9003 is H4. But is that H4 the same spec and build as a US-spec 9003 as regards horizon, glare, aim, etc?

Thanks!

 

[Hooch]

I believe there are some minor differences between the H4 and 9003. If I recall correctly, the H4 filament is stronger to better resist vibration. The 9003, on the other hand, has tighter tolerances on the filament position.

 

[ChrisW]

and ultimately more precise placement on the fillament will produce better light output by placing the light source at best focus point for the given optics. I belive most H4 and 9003 bulbs are E1 and DOT rated.

 

[moribundman]

9003 is the DOT code for the H4 Euro bulb designation. The bulbs,sockets and specs are identical. Some makers make longlife, high-power, etc versions. For example, Philips makes these H4 versions:

Premium
LongerLife
VisionPlus
BlueVision
SilverVision
Power2Night
NightGuide