Just curious to see what the difference is, i tried looking it up on the internet and came up empty. The bulbs look almost identical. They both have two filaments, one for high and one for low. the only difference i have found is that on the H4U, the low beam filament is shielded....Is that all there is? Does the shielded filament make a difference in the lighting? Thanks....Brian

 

Bump!!

 

one last

 

Not sure, have never seen an H4U bulb myself. I know the H4 bulbs have a partial shield on the low beam filament to cut off the upward part of the beam.

 

I have looked and looked, i think they are exactly the same, thanks for the info tho 4crawler...